新民主主义革命时期，统一战线对于我们党夺取新民主主义革命胜利发挥了重要的作用。研究中国共产党在新民主主义革命时期的统战工作对于研究党在新民主主义革命时期取得的重大成就和历史经验有着重要意义。中国共产党，中国国民党是近代中国最重要的两个政党，对国民党的统战工作是我们党在新民主主义革命时期统战工作的重要组成部分。孙科作为国民党重要人物，中国共产党在1924-1945年间对其进行的统战工作对于维护两次国共合作，夺取全民族抗战的胜利发挥了重要作用，并积累了诸多统战工作的经验与教训。

中国共产党的统一战线理论源自于马克思恩格斯列宁等无产阶级革命导师的关于建立无产阶级统一战线的论述。中国共产党早期革命家及以毛泽东同志为核心的党的第一代领导集体将马克思主义统一战线理论与中国具体实际相结合，在革命实践中丰富发展了中国共产党领导下的统一战线理论。

中共二大在我党统一战线发展史上具有开创性意义。中共二大后，为实现民主革命纲领和建立民主联合战线，中共中央在共产国际指导下，派遣李大钊、陈独秀等与国民党领导人孙中山会晤，商讨国共合作事宜，中共三大与国民党一大确立了第一次国共合作和国民革命统一战线政策。孙科，作为国民党的重要人物，在美国成长，受到资产阶级自由主义思想和其父亲孙中山的反帝反封建革命活动影响。他参与了孙中山领导的民主革命和国民党改组工作。孙科虽然对俄国革命胜利感到鼓舞，但他不支持在中国进行共产主义革命。因而在国民党一大中孙科表示反对联共政策，遭到毛泽东瞿秋白等人批评。孙中山逝世后，孙科参与了西山会议派活动，共产国际与中国共产党为了维护国民革命联合战线，与孙科在上海进行了谈判，动员他返回广州参加国民党二大，以便于瓦解国民党右派。在武汉国民政府时期，孙科政治立场发生变化，支持孙中山的联俄、联共、扶助农工的三大政策，中国共产党方面对其积极争取。大革命时期对孙科的统战工作虽然受到右倾错误的影响，但为后来的统战工作积累了宝贵经验。

1927年,蒋介石发动了四一二反革命政变,7月15日，汪精卫召开分共会议，标志着第一次国共合作的破裂。这一时期以蒋介石为首的国民党新军阀在英、美帝国主义的支持下，建立起代表地主阶级、买办阶级利益的南京国民政府。在土地革命时期，中国共产党建立和巩固工农民主统一战线，开辟了一条适合中国国情的农村包围城市武装夺取政权的革命道路。1928-1930年间，工农民主统一战线进一步确立。这一时期国共两党斗争激烈，中国共产党对孙科以批判为主，将其定性为地主买办阶级。对于孙科参加反蒋活动，中国共产党对其评价为国民党内部的争权夺利，中国共产党注意到了孙科与蒋介石在对日作战问题上的不同，但因当时国共双方紧张关系以及党内“左”的路线影响，统一战线理论与政策还不够成熟，还没有意识到处理与资产阶级关系的重要性，因此对包括孙科在内的主张抗日的国民党人士以批判为主。

1935年华北事变后民族危机加剧，同年共产国际七大召开，中共中央和中央红军抵达延安。中国共产党根据国内外局势变化确立抗日民族统一战线方针，扩大统一战线范围，并恢复与国民党高层的接触，从“反蒋抗日”到“联蒋抗日”与“逼蒋抗日”。随着抗日民族统一战线的确立，中国共产党注意到孙科的抗日主张，并对其进行统战工作。在中国共产党的争取下孙科响应了宋庆龄的号召主张恢复三大政策，主张释放政治犯，与中国共产党一道营救七君子。通过对孙科的统战对促成停止内战一致对外，促成第二次国共合作起到积极意义。

1937年全民族抗战爆发后，中国共产党积极推动以国共合作为基础的抗日民族统一战线，党的统一战线理论与政策在这一时期全面成熟并取得巨大成功，为抗日战争最后胜利奠定坚实基础。全面抗战爆发后，孙科主张积极抗日，反对对日妥协，主张发展与苏联的友好关系并争取苏联对华援助。抗战后期提出对日清算，施行民主等具有一定进步意义的主张。中国共产党对孙科的爱国主张予以肯定，并对其进行统战工作，在统战工作中将团结与批评相结合，对于维护国共合作，反对蒋介石独裁，壮大大后方民主力量起到了积极作用，并积累了对国民党高层人士的统战经验。

During the period of the New Democracy Revolution, the united front played a crucial role for the Communist Party of China in winning the New Democratic Revolution. Researching the Party's united front work during the New Democracy Revolution period is of great significance for studying the major achievements and historical experiences gained by the Party during this period. The Communist Party of China and the Kuomintang were the two most important political parties in modern China, and the united front efforts targeting the Kuomintang constituted an important part of our Party's work during the New Democracy Revolution period. As a significant figure in the Kuomintang, Sun Fo's role in the united front work conducted by the Communist Party of China from 1924 to 1945 played a significant role in maintaining the two rounds of cooperation between the Nationalists and the Communists, achieving victory in the comprehensive War of Resistance, and accumulating a wealth of experience and lessons from the united front work.

The theory and strategy of the united front of the Communist Party of China originated from the discussions on building a proletarian united front by the teachers of the proletarian revolution, such as Marx, Engels, and Lenin. Early revolutionaries of the Communist Party of China, along with the first-generation leadership collective centered around Comrade Mao Zedong, integrated the proletarian united front theory with China's reality and the fine traditional Chinese culture. Throughout the revolutionary process, they enriched and developed the theory of the united front under the leadership of the Communist Party of China. The Party's Second Congress was of pioneering significance in the history of the development of the united front.

Following the Second National Congress of the Communist Party of China (CPC), to fulfill the program of the democratic revolution and establish a democratic united front, the CPC Central Committee, under the guidance of the Comintern (Communist International), sent Li Dazhao, Chen Duxiu, and others to meet with Kuomintang (KMT) leader Sun Yat-sen to discuss cooperation between the two parties. The Third Congress of the CPC and the First Congress of the KMT established the first cooperation between the Nationalists and Communists and formulated the policy of a united front for the National Revolution. Sun Fo, a significant figure in the KMT who grew up in the United States, was influenced by bourgeois liberalism and his father's anti-imperialist and anti-feudal views. He participated in the democratic revolution led by Sun Yat-sen and the reorganization of the KMT. Although inspired by the success of the Russian Revolution, he did not support a communist revolution in China. At the First Congress of the KMT, he opposed the policy of cooperation with the Communists and faced criticism from Mao Zedong, Qu Qiubai, and others. After Sun Yat-sen's death, Sun Fo engaged in the activities of the Western Hills Group. The Comintern and the CPC negotiated with Sun Fo in Shanghai to maintain the united front of the National Revolution, persuading him to return to Guangzhou to participate in the Second Congress of the KMT, which helped to undermine the KMT's right wing. During the Wuhan Nationalist Government period, Sun Fo's political stance changed, supporting Sun Yat-sen's policies of alliance with Russia, cooperation with the Communists, and assistance to peasants and workers, with the Communist side actively seeking his support. Despite the right-leaning errors affecting the united front work with Sun Fo during the Great Revolution, it accumulated valuable experience for later efforts.
    In 1927, Chiang Kai-shek and Wang Jingwei launched anti-revolutionary actions in Shanghai and Wuhan, respectively, marking the failure of the Great Revolution and the complete rupture of the first cooperation between the Nationalists (KMT) and the Communists (CPC). During this period, the KMT, led by Chiang Kai-shek and supported by British and American imperialism, established the Nanjing National Government, which represented the interests of the landlord and comprador classes. During the Agrarian Revolutionary War, the CPC created and consolidated the worker-peasant democratic united front, exploring a revolutionary path that was in line with China's actual conditions. This path involved encircling the cities from the countryside through armed struggle to seize power. Between 1928 and 1930, the worker-peasant democratic united front was further established.

During this period, the struggle between the KMT and the CPC was intense. The CPC primarily criticized Sun Fo, categorizing him as part of the landlord and comprador classes. Regarding Sun Fo's participation in anti-Chiang activities, the CPC viewed it as an internal struggle for power within the KMT. The CPC noted the differences between Sun Fo and Chiang Kai-shek on the issue of war against Japan and worked on Sun Fo through secret party members close to him. However, due to the tense relations between the KMT and CPC at the time and the influence of the "left" line within the party, the theory and policy of the united front were not yet mature. The importance of handling relations with the bourgeoisie was not fully recognized, and thus, the CPC primarily criticized nationalists within the KMT, including Sun Fo, who advocated resistance against Japan.

After the North China Incident in 1935, the national crisis intensified. The Communist Party of China, in response to changes in the domestic and international situation, established the guidelines for the Anti-Japanese National United Front, expanding the scope of the united front and restoring contact with the high levels of the Kuomintang (KMT). The strategy shifted from "anti-Chiang for resisting Japan" to "ally with Chiang to resist Japan" and "pressure Chiang to resist Japan". With the establishment of the Anti-Japanese National United Front, the CPC began to make contact with the KMT, including its military and political high command as well as local power factions. The CPC recognized Sun Fo's advocacy for resisting Japan and engaged him in united front work. Under the efforts of the CPC, Sun Fo responded to Song Qingling's call to restore the "Three Principles of the People" and the united front efforts with Sun Fo played a positive role in achieving a cessation of the civil war and uniting against external threats, contributing to the formation of the Second United Front between the KMT and CPC.
   After the full-scale outbreak of the War of Resistance against Japan in 1937, the Communist Party of China (CPC) actively promoted the Anti-Japanese National United Front based on cooperation between the KMT and CPC. The Party's theory and policy on the united front fully matured during this period and achieved great success, laying a solid foundation for the ultimate victory in the war against Japan. Throughout the war, the CPC maintained a patriotic stance, affirmed Sun Fo's patriotic advocacy, and engaged in united front work with him. In this united front work, the CPC combined unity and criticism, playing a significant role in maintaining cooperation between the KMT and CPC, opposing Chiang Kai-shek's dictatorship, and strengthening the democratic forces in the rear areas.