In this study, a typical Branch maogou valley in Wangmaogou watershed of loess Plateau was selected asss the research object. Consumer uav was combined with 1 : 500 tilt photo grammetry.The flight control software GS RTK App is used to plan the zigzag course and simulate the effect achieved by multi-lens tilt camera. Meanwhile, tilt and orthographic images are obtained with the help of ground control points. Pix4D, Smart3D and other software were used to construct a high-resolution 3D model of erosion gully, as well as DOM and DEM. According to the detailed evaluation of the obtained results, both the horizontal error and elevation error of the two methods can meet the requirements of the Internal Practice Specification for Low Altitude Digital Aerial Photogrammetry (GH/Z 3003-2010). At the same time, the point cloud data obtained is more dense and uniform than RTK manual measurement, which solves the problem of reduced measurement accuracy in the area inaccessible to people due to the complex and steep terrain in the erosion ditch. On the premise of reasonable application, this method can replace hand-held RTK manual measurement, and its convenience, maneuverability and accuracy make it have the potential of popularization and application in watershed erosion monitoring.
