Abstract: Common prosperity is the essential requirement of socialism, and achieving common prosperity for all the people is the essential feature of Chinese modernization. The multi-source theory is used to systematically analyze the century-old evolution of the common prosperity policy of the Communist Party of China. The study found that the Communist Party of China common prosperity policy can be roughly divided into four historical stages: preliminary exploration, tortuous development, advancing with the times and solid promotion. The changes of the Communist Party of China common prosperity policy at different stages are all the results of the joint efforts of the three streams, namely, the prominent practical problems of common prosperity faced by the Party, the political situation faced and the political mission undertaken, as well as the cognitive achievements and action plans of common prosperity inside and outside the Party. In the new development stage of common prosperity, we should optimize the policy formulation from four aspects: problem streams, political streams, policy streams and “policy windows”, which may have some reference value.