Relief amplitude is an important factor that impacts the spatial pattern of population distribution. However, the relationships between the population distribution patterns and relief amplitude are not clear yet. It is essential to understand these correlations to enhance the realization of a man-land relationship and sustainable management for a population. This study quantitatively analyzes the impact of relief amplitude on the population agglomeration/shrinking pattern from 1995 to 2010 on the basis of the DEM (Digital Elevation Model)and population census data and the methods to determine population density and aggregation degree. The results show that (1) the fluctuation of terrain was mainly moderate and low in the study area, with the relief amplitude between 0 to 200m having the highest proportion of 30.34%, and the level of 200 to 400m accounting for 30.33% of the study area; (2) the difference in relief amplitude had an important effect on the regulation of population distribution pattern, leading to high population density in the east and low in the west. Between 1995 and 2010, the regions with frequent population changes were mainly concentrated in the areas with small or medium relief amplitude; (3) in general, no obvious changes were observed in the population agglomeration/shrinking pattern. In the period from 1995 to 2010, the population movement mainly occurred in the areas with small or medium relief amplitude, and the proportion of the inflow population was much larger than that of the outflow population. The mountainous plateau areas with large relief amplitude mostly had relatively stable populations. These conclusions generally demonstrate the correlations between population distribution patterns and relief amplitude, and could provide references for the sustainable population management in southwestern China.