It is necessary to check the trajectory of the robot to avoid collisions in order to ensure manmachine safety. Aiming at the problem of collision detection in robot simulation system, a hierarchical triangle patch collision detection model was researched based on octree structure, the bounding box interference test was used as coarse detection, and the intersection detection of triangle patch was used as accurate detection. In order to improve the efficiency of triangle intersection detection, a triangle interference algorithm based on intercept equation was proposed. The triangles in a threedimensional space were mapped to a twodimensional plane, and the complicated calculation of scalar and vector discriminant in traditional triangle intersection detection was avoided. Finally, it was applied to the robot simulation system to verify the effectiveness of the collision detection algorithm.