Abstract: Through structural analysis and 3D geological structure survey, the thrust nappe structure is discovered in the diamond metallogenic belt of Wafangdian area, which consists of the external slip system in hanging wall, autochthonous system in footwall and thrust fault. The thrust nappe that generally pushes from SEE to NWW in nearly horizontal low angle was formed in the Middle-Late Jurassic. Based on the discovery, it is inferred that there is great prospecting potential in the footwall, which provides new thoughts for diamond prospecting and basic geological research.