The equalization of basic public services is the logical premise for achieving common prosperity. There is still a certain gap between the level of basic public services in small and medium-sized cities and the goal of “equalization”. In order to scientifically evaluate the basic public service level of small and medium-sized cities and firmly promote the realization of the goal of common prosperity in China，this paper，based on the analysis of the impact mechanism of basic public services on common prosperity，has built an evaluation index system of basic public service level of small and medium-sized cities with the goal of improving the service system，integrating urban and rural areas，and making service supply efficient. It is expected to provide reference for evaluating the basic public service level of small and medium-sized cities.