As an important characteristic of Chinese modernization, common prosperity entails the rule of law, which plays the roles of leading, regulating and securing the process of achieving common prosperity. In this process, the three roles should have their own characteristics in form and contents. The leading role of the rule of law mainly refers to the impact of legal spirit and principles on the goal of the subject; the regulating role means the influence of specific legal rules on the behavior of the subject; the securing role is mainly the positive influence of promoting common prosperity and achieving solid outcomes through the implementation and application of laws. The three roles also have different manifestations due to different subjects and different stages of law-based governance.