随着我国公共服务事业的不断发展，有越来越多的人选择加入志愿者组织，成为志愿者。志愿服务为国家的发展和社会的进步做出了重要贡献。伴随着社会大众的需求多样化，志愿服务的项目种类和数目也在相应地日益增加。志愿服务相关的政策与法规也在逐步完善。然而，在此期间，我国志愿服务工作也出现了许多问题，其中最突出的问题就是志愿者服务的持续时间不够长。该问题会使志愿服务项目顺利开展的难度加大，进而降低社会服务的质量，增加志愿者组织的运作成本，造成各种社会资源的浪费。
      大学生作为志愿者群体中的主力军，具有相对较高的知识水平和较为先进的思想理念，是非常具有发展潜力且能体现志愿者精神的核心群体。在为社会提供志愿服务的过程中，大学生志愿者也能锻炼自己、将理论知识与实践相结合，培育个人综合素质。志愿服务将大学与社会联系起来，起纽带的连接作用，但由于大学生群体年龄小，没有充足的社会经验，情绪相较而言没有那么稳定，更容易情绪化和和冲动，志愿服务持续性不强的问题也更加突出。研究如何提升大学生志愿行为的持续性非常有现实意义。
      本研究将大学生参与志愿服务的动机定为切入点，研究其如何影响志愿行为的持续性，选用学术界已经使用过的成熟量表，构建理论模型，重点研究志愿者角色认同在其中的中介作用和组织支持在其中的调节作用。本研究采用问卷调查法与数据分析法，利用问卷星软件，选取珠海市各大高校的志愿者群体为研究对象进行线上的数据收集，匿名填写以求数据真实。通过数据分析得出，珠海市大学生志愿者群体志愿服务持续性整体偏低，与实际情况相一致，另外，志愿者的服务动机对志愿行为的持续性有显著的正向影响，角色认同在志愿动机对志愿服务持续性的影响机制中起部分中介作用，组织支持在志愿动机对志愿服务持续性的影响机制中起调节作用。
      最后，本文针对得出的结论，从组织和个人层面分别提出增强大学生志愿服务持续性的办法，例如高校应加强对志愿活动的宣传，以此来提升学生参与志愿服务的动机水平，志愿者组织应提升组织管理水平、完善后勤保障，志愿组织和服务对象都应该尊重和认可志愿者的付出等。

      With the continuous development of public service in China, more and more people choose to join volunteer organizations and become volunteers. Voluntary service has made important contributions to the development of the country and the progress of the society. With the diversification of the needs of the public, the types and number of volunteer service projects are also increasing accordingly. Voluntary service related policies and regulations are also gradually improved. However，at the same time,we can still find some problems, among which the most prominent one is the problem of the short duration of volunteer service behavior in China. This problem will make it more difficult to carry out volunteer service projects smoothly, thus reducing the quality of social services, increasing the operating costs of volunteer organizations, and resulting in the waste of various social resources.  
      As the main force of the volunteer group, college students have relatively high level of knowledge and advanced ideas. They are the core group with great development potential and can embody the volunteer spirit. In the process of providing volunteer service for the society, college student volunteers can also exercise themselves, combine theoretical knowledge with practice, and cultivate individual comprehensive quality. Volunteerism serves as a link between the university and the community.However, as a group of college students, they are young in age and lack of social experience. Their emotions are less stable, and they are more likely to be emotional and impulsive. The problem of poor continuity of volunteer service is also more prominent.
      Selecting the motivation of college students to participate in voluntary service as the entry point and analysing how it affects the continuity of voluntary behavior. This study built a theoretical model by referring to the mature scale used in previous studies, and focused on  volunteer role identity’s mediating role and organizational support’s moderating role. In this study, questionnaires and data analysis methods were used to collect online data from volunteers in universities in Zhuhai and they fill in the data anonymously. Through data analysis, Zhuhai college students volunteer groups showed low service persistence overally. In addition,the volunteer service motivation can significantly affect the behavior of sustainability. Role identity mediates the relationship between volunteer motivation and voluntary behavior persistence. Organizational support moderates the relationship between volunteer motivation and volunteerism persistence.  
      Finally, to conclude, this article puts forward ways to increase the sustainability of college students' volunteer behavior from both the organization level and the individual level. For example, students' motivation level can be enhanced by strengthening the propaganda of volunteer activities , the volunteer organizations should improve their management ,the whole society should respect volunteers more, and so on.