Abstract: Taking Huaihe river basin as the study area and county level as the research unit, selecting data of population and population density of the Huaihe river basin since the 1980s as the research indicators, the spatial pattern and evolving trend were studied through the related analysis of population density, unbalanced index, population gravity center model, shiftshare analysis and spatial autocorrelation analysis. The results showed that the rate of population growth became  slower; the population density was more than four times than the average of national’s. There was certain spatial relevance on population distribution;it formed population agglomeration area in the upstream counties of various tributaries of the Huaihe river. The population distribution was imbalanced and such situation was enhanced. The population gravity center slowly moved to the east west.