春秋中晚期，即楚庄王即位后至惠王前期（公元前615年—公元前476年），楚国的政局经历了反复变动。通过对楚之二卿士令尹、司马和两职之辅左尹、右尹、左司马和右司马这中枢“六官”任职人选的考察，再以可见的中枢其他官员的活动情况为补充，可以对该时期楚国的政局有大致的把握。春秋中期以前，若敖氏之族垄断楚国朝政，其在为国贡献卓著的同时，对王权的威胁也日益严峻。楚庄王消灭若敖氏后，为避免一族独大的局面再现，将公子势力引入中枢以加强王权。共王朝（公元前590年—公元前560年）是“群公子政治”的时代，群公子在中枢担任要职，在楚国的内政和外交活动中都非常活跃。然而公子势力的发展壮大导致楚国产生了“国多宠而王弱”的局面，公子对时王王权的威胁因其具有君位继承的合法资格和权利而显得更为直接而严重。楚康王继位后调整政局，令蔿氏、屈氏进入中枢任职掌权，丰富朝臣组合，并逐步将公子挤出中枢核心以限制其势力的发展。世族从与公子共享政权到逐渐在中枢中占据优势，这是康王朝（公元前559年—公元前545年）楚国政局的变化。康王之后即为郏敖（公元前544年—公元前541年），令尹公子围趁王年幼弑君篡位，自立为灵王。楚灵王对公子十分警惕，延续了康王重用世族成员、打击公子势力的统治策略，还采取了诸多手段以加强王权。该时期（公元前540年—公元前529年）楚中枢仍是蔿氏、屈氏之人担任要职，且朝臣组合更为丰富多样，而公子却式微了。平王至惠王前期（公元前528年—公元前476年）楚国的政局可以以昭王十年（公元前506年）吴师入郢之役和惠王十年（公元前479年）白公胜之乱两大事件为界分为三个阶段。平王同样是以公子之身份篡立，其统治时期（公元前528年—公元前516年）公子势力不昌，新兴世族入主中枢掌权执政，统治集团内部矛盾斗争复杂尖锐，此一局面一直持续至昭王十年吴师入郢前。昭王复国后，群公子因政才突出、复国有功而代替世族重回中枢执政，并在昭王后期形成了以楚王近亲为核心的政治秩序。公子主政之局面于惠王十年白公胜之乱后为公孙所代，权力由公子转移到了公孙手中。通过以上考察，我们可以发现春秋中晚期楚国政局的变迁有以下特点：权力高度集中于王族，且以楚王为核心，王权未下移；政局变迁是楚王、公子、世族三方势力相互斗争的结果；官员更替与政局变迁之间存在相互作用。

In the mid to late of Spring and Autumn period, that is king Zhuang of Chu’s reign to the early years of king Hui of Chu’s reign（615BC to 476BC）, the political situation of Chu experienced repeated changes. By investigating the candidates of the two main ministers of the state of Chu, the Ling Yin and the Si Ma, with their assistants the left Yin, the right Yin, the left Si Ma and the right Si Ma, which could be regarded as the dominating six officials in the situation of the State of Chu, and supplemented by the activities of other central officials written in historical documents, we can have a general grasp of the political situation of Chu in this period. Before the middle of the Spring and Autumn period, the clan of Ruo’ao monopolized affairs of the state of Chu, they made outstanding contributions to the country, but the threat of the clan of Ruo’ao to the royal power was increasing severely at the same time. After king Zhuang of Chu wiped out the clan of Ruo’ao, to avoid the situation that one clan monopoly political power in the centre to reappear, he brought princes to the central government to strengthen his power. Reign of king Gong of Chu (590BC to 560BC) was the age of princes’ politics. Princes occupied important posts in the central government, they participated in interior affairs and foreign affairs of the state of Chu actively. However, development of princes’ influence leaded to the situation that there were many princes which were doted on by the king who were on the throne and power of the king was getting weaker.The threat of the prince to the royal power of the king was more direct and serious because prince has the legal qualification and right to succeed to the throne. After king Kang of Chu succeeded to the throne, he adjusted the political situation, made the clans of Wei and Qu enter into the central government and be in power, enriched the combination of officials, and gradually squeezed princes out of the central core to limit their power. It was a change of political situation of reign of king Kang of Chu (BC559 to BC545) that the hereditary clans changed from sharing power with princes to gradually having an advantage over them in the central government. After king Kang of Chu, Chu Jia’ao (BC544 to BC541) succeeded to the throne, prince Wei, who held the post of Ling Yin in this time, killed Chu Jia’ao while he was young.Then prince Wei usurped the throne, this was king Ling of Chu. King Ling of Chu was very vigilant of princes and he continued king Kang’s ruling strategy of putting hereditary clans in the important position and striking princes’ power. And he also took many measures to strengthen the royal power. During his reign (BC540 to BC529) , the clans of Wei and Qu still held the important posts in the central government and the combination of officials was richer, but prince’s power was fading away. The political situation from king Ping’s reign to the early period of king Hui’s reign (BC528 to BC476) can be divided into three stages by two major events: the battle of army of the state of Wu invaded into the capital city of the state of Chu called Ying in the tenth year (BC506) of king Zhao’s reign and the rebellion staged by Bai Gong Sheng in the tenth year (BC479) of king Hui’s reign. King Ping of Chu also usurped the throne as a prince. In his reign (BC528 to BC516) , princes wasn’t powerful. Some new hereditary clans came into the central core to hold power, and internal contradictions and conflicts of the ruling group were complex and sharp. This situation continued until the tenth year of king Zhao’s reign when the army of the state of Wu invaded into Ying. After king Zhao of Chu restored the state, princes took the place of hereditary clans and they returned to the central government to come to power because of their outstanding political ability and remarkable contributions to the restoration of the state. In the late period of king Zhao’s reign, it formed a political order centered on the close relatives of him in the central government of the state of Chu. The situation that princes ruled the government was replaced by a new one that their sons came into power after the rebellion of Bai Gong Sheng broke out in the tenth year of king Hui’s reign, so the power was transferred from princes to their sons. Through the above investigation, we can find that changes of the political situation of the state of Chu in the mid to late of Spring and Autumn have the following characteristics: the power was highly centralized in the royal clans, and the king of Chu was the core, and devolution of the royal power didn’t appear; changes of the political situation was the result of the struggles between three forces of the king of Chu, the princes and the hereditary clans; there are interactions between official turnovers and changes of the political situation.