A generating algorithm of multi-axis NC machining tool-path for triangular mesh surface model was proposed,which had five steps:first,the special index structure of triangular mesh surface model was established based on the R*-tree;second,section data were computed through intersecting between the mesh model and the tool-path section according to the special index structure; third,the transient processing area was obtained;forth,the cutter location points were generated by means of the relevant computing modes;fifth,the cutter location points were sorted with the minimum spanning tree algorithm.It is proved that it can generate multi-axis NC machining tool-path for all kinds of triangular mesh surface models accurately and efficiently.