The invention discloses a DEM-based terrain sketch automatic drawing method, which comprises the following steps of 1, acquiring DEM data of a to-be-drawn terrain sketch area, and extracting terrain feature line elements in the area; 2, dividing the to-be-drawn area into a close shot area, a middle shot area and a distant shot area by taking the basin division line as a visual hierarchical division line; 3, reserving all topographic feature line elements of the close-range area; and only reserving the visual contour line of the middle scene area; calculating the area of a closed area defined by the visual contour lines in the distant view area, and selecting the visual contour line where the boundary of the first N closed areas with the maximum area is located as the terrain characteristicline element reserved in the distant view area; and 4, combining topographic feature line elements reserved in the near scene, the middle scene and the distant scene into a topographic sketch map. According to the method, the DEM is used for drawing the topographic sketch map, the automatic drawing of the sketch map is achieved, the topographic sketch map drawing technology is simplified, and thetopographic sketch map capable of reflecting rich geographical environments and topographic structures can be rapidly provided.