The method that avoiding repeatedly reading a triangular facets information is proposed by studying the redundant data of STL file, and the index relation is built up by the 6, r, z coordinates of triangular facets. 研究了STL文件读取时的冗余数据,提出了避免多次重复读取同一个三角面片信息的方法,并通过三角面片顶点的θ,r,z坐标在各三角面片之间建立起了索引关系。