Abstract: In order to satisfy the technological requirements of the automatic tape-laying on freeform surfaces, prepreg tape path is generated. The method adopts triangle meshes to approach a freeform surface. It uses a commercial CAD software to output surface triangle list （STL）files for analyzing the surface and reconstructing the triangle mesh information to establish the relation ship between triangles, sides, and vertexes. The prepreg tape path is generated by applying the “Natural Path” theory on a freeform surface. The calculation of the path on surface boundaryies is studied and a method is advanced to solve the singularity question of passing the triangle vertex. An example shows that the method of calculation for generating the prepreg tape path on surfaces is feasible

Key words: surfaces, automatic tape-laying, triangle mesh, reconstructing information, natural path