Abstract: To satisfy the requirements for refined management of water conservancy projects, this paper presents a method for generating multi-view orthographic images from oblique 3D models. The method adopts the best-fitting plane of terrain units as the projection surface to produce multi-view orthographic images, which can precisely characterize the geometric configuration of complex objects and comprehensively reproduce their fine structures. Validated by experiments at the Xiluodu Hydropower Station, the generated orthographic images achieve root mean square errors of 3.2 cm in the X plane direction, 3.4 cm in the Y plane direction, and 5.8 cm in the elevation direction. It enabled centimeter-level high-precision measurement and distortion-free representation of vertical surface information for hydraulic structures, thereby providing efficient and accurate data support for refined monitoring and safety evaluation of water conservancy projects. The results of Xiluodu Hydropower Station experiment show that this method breaks through the limitation of using the horizontal plane as the projection surface, can maximize the expression of the facade surface information of complex targets, effectively solves the problem that oblique 3D models or close-range photogrammetry cannot effectively express the surface information of ground objects. The research results can provide references for the precise management of water conservancy projects.