<p>Counties have been continuously serving as basic administrative divisions throughout ancient and modern China, and population has always been the focus of national governance. Thus county-level population data is of great significance for understanding spatial pattern of governance in ancient China, and is also basic data for studying urban system of ancient China. However, due to twists and turns in history, most of the county population statistics before Qing Dynasty (1644~1911AD) have been lost, and need to be obtained through data reconstruction process. Based on publicly available historical statistical data on prefecture level, this study combines raster terrain data and vectorized historical geographic data, simulates population distribution of 4 representative dynasties through geo-calculation method, and estimates the population data of 6,089 counties in the years 2, 742, 1102 and 1820AD. By preliminarily reconstructing population distribution and county-level population sequence of representative time slices, the evolution of key administrative districts and habitat regions in different eras has been revealed.</p>