This study is aiming at the problems of slow collision detection speed of bounding box, low efficiency of triangle intersection detection, and triangulation in regions where complex intersecting lines are segmented that exist in Boolean operation of triangular mesh model in underground space engineering. The orientation calculation method of underground space engineering is put forward, and the precise definition of bounding box is realized. A simple method to realize the fast intersection detection algorithm between triangles is presented, the process of transforming the projection of intersecting lines into scalar and then judging is eliminated, and the efficiency of triangle intersection detection is improved. On the basis of Delaunay triangulation robust algorithm, numbering method of intersection position is improved. Central axis region division method and hierarchical subdivision triangulation method are proposed, which can divide all the regions of mixed complex intersections in one traversal. A subdivision triangulation method by comparing the cosine value of internal tension angle is proposed, and the subdivision triangulation of polygon is optimized. The feasibility of the algorithm is verified by practical engineering application.