The algorithm to obtain intersecting lines from section and equidistance surface is one method of resolving the problem of obtaining NC machining procedure from points cloud data. As far as cutter paths obtained by section method are concerned, if intersecting lines using tangent plane and processed curved surface are obtained directly, it will be a quite complicated process and lead to divergent iteration operation because of inconsiderate design algorithm, and therefore it leads to the failure of obtaining intersecting lines. So the method of obtaining intersecting lines from section and equidistance surface is adopted. And this paper put forward and has realized one new algorithm. The calculation is simple and the algorithm is stable. It avoids the interference of cutting tool paths.