The invention provides an unmanned aerial vehicle aerial photography image automatic generating line drawing method based on a desert area. The method comprises the following steps: designing a flightroute of an unmanned aerial vehicle; arranging an automatic identification type image control point or an automatic identification type target in a measuring area; an unmanned aerial vehicle carriedcamera or radar flying and acquiring images according to a preset airline; importing the images into aerial triangulation software to carry out aerial triangulation, and generating an LAS data file; importing the LAS data file into point cloud processing software to carry out point cloud processing and generating a TIN (Triangulated Irregular Network); performing point cloud resampling on the TINaccording to a mapping scale, editing a resampled terrain point, and importing the edited data into topographic map mapping software to automatically carry out contour line drawing and generating measuring area line drawing. According to the method in the invention, the unmanned aerial vehicle is used for measuring a target area, after the images are spliced, the method is not performed accordingto the traditional unmanned aerial vehicle mapping process, the cloud data processing flow is combined to directly generate the images into point cloud, the point cloud is resampled, an elevation point is plotted so as to manufacture a DLG (Digital Line Graphic), the precision is higher, and the efficiency is higher.