Considering that some triangular mesh models are inconvenient for storage, analysis and display due to enormous data volume, a simplification algorithm for triangular collapsed mesh combining with mesh refinement was put forward. In this method,the modified coordinates for three vertexes of the triangle to be collapsed were determined by using the 3 surface subdivision method, and the position of the folding point was preliminarily determined in accordance with the modified coordinates; then the Laplacian coordinate of the folding point and normal information of the original triangle were introduced to update the folding point position; finally, the collapse cost was caculated based on volume error of the area after triangle collapse and flatness of the collapsed triangle, thus enabled the mesh to preferentially carry out collapse simplification from relatively flat area with few feature points. Experimental test and data analysis were established in multiple models, and result indicates that the method can effectively simplify the mesh data. Compared with three simplification methods of different types, the method can achieve the highest simplification efficiency, and can, at the same time, effectively maintain geometric characteristics of the mesh model and control quality of the simplified triangle.