While the expanding post-doctoral group in China is faced with practical challenges such as living situation, academic development and independence, the academic circle lacks internal and systematic studies on their job satisfaction and influencing factors. In order to promote the relevant institutional reform and improve the job satisfaction of post-doctoral groups, based on the data of the global post-doctoral survey conducted by Nature in 2020, and under the theoretical framework of the satisfaction index model, and with the analysis of the structural equation model, it is found that the global postdoctoral job satisfaction index score is 63.16, which is in the basic satisfaction stage. Organizational safeguards, cooperative mentor support and job expectations can significantly positively predict postdoctoral job satisfaction, and the overall effect of cooperative mentor support is higher. Job expectations can not only directly predict postdoctoral job satisfaction, but also indirectly affect satisfaction through two mediating variables of organizational safeguards and cooperative mentor support. Organizational safeguards exert a chain mediating effect by influencing cooperative mentor support. Postdoctoral researchers with different genders, mobility patterns and working years have different perceptions of job satisfaction. Therefore, it is suggested that the relevant policies and institutions for post-docs in China should clarify their professional status, enhance the level of organizational support, strengthen the support of cooperative supervisors, and pay attention to the actual needs of different post-docs.