Quality evaluation of census data is an important topic in demographic research. Studies on the quality of census population data are few in China， and the evaluation of provincial and municipal population data is even rarer. This paper does not start with the direct population data， but uses the saturated mean rigidity of the number of mobile users in provinces and cities， and measures and analyzes the total population data of provincial， regional and prefecture level cities according to the law of large numbers and pinch theorem. The results show that： in the seventh national population census(the 7thNPC)in 2020， the quality of census data of permanent residents in provincial levels is relatively high， and the quality rate of standardized provincial data is mostly more than 95%. There are still more permanent residents in the provinces with net inflow of population， while there are more permanent residents in the provinces with large outflow of population. Taking Guangdong Province as an example， the quality of census data in various cities has been greatly improved， and there is no room for human operation of population data in the future. The inflow of migrant labor in the eastern coastal areas will continue to decline, but the pressure of education, medical care, housing and pension in these areas is lower than that in the outflow areas. Maintaining the annual population of 10 million new births should be a goal. Six systematic countermeasures are proposed to cope with the population and labor force changes in China.