Provided are a device and a method for extracting a terrain boundary, including: a grid creating module configured to divide a region which is determined based on measured contour line data of a target terrain, to form a regular grid including multiple grid units; a data analyzing module configured to assign a first standard value or a second standard value to each of the multiple grid units based on the number of elevation points included in the grid unit, to form a final grid region, where the final grid region is a region including all grid units having the first standard value; and a boundary extracting module configured to extract a terrain boundary based on the final grid region.