At present, there is still no more reliable data in China that can challenge the reliability of the seventh national census data under the background of normalized COVID-19 pandemic control, comprehensive two-child policy implementation and big data technology. Compared with the data of the seventh national census in 2020, it is found that there is a quite deviation in the estimation of some population data in the sampling survey of population change of the National Bureau of Statistics from 2011 to 2019, which leads to severe underestimation of the scale of population migration and urbanization in China. The speed of urbanization of China’s permanent residents has not slowed down, but the speed of urbanization of household registration is relatively low, which results in the phenomenon of semi-urbanization becoming more and more intense. The continuous expansion and long-term underestimation of the scale of floating population have led to a series of problems such as the mismatch of public resources and the differential treatment of settled groups. Therefore, we should re-examine the stage characteristics and potential negative effects of the rapid development of China’s urbanization, the expansion of the scale of floating population and the increasing separation of registered and actual residences in municipal districts.