Based on the DEM raster image data with a resolution of 60 m × 60 m in the Sanjiangyuan region, the topographic heterogeneity in the Sanjiangyuan region was analyzed by calculating and processing the topographic relief, elevation standard deviation, terrain heterogeneity and surface roughness indexes. The results show that the overall terrain elevation of the Sanjiangyuan area is high, and the surface undulations are large. The southern and southeastern parts of the region are the places with the most dramatic terrain changes. The absolute values of terrain undulations, elevation standard deviation and surface roughness are large. In the central and western regions, the terrain change is small, the relief degree is small, the elevation standard deviation and the surface roughness are small.