The existing studies on the CNC incremental sheet metal forming technology are all for the sheet metal parts with either concave peaks or convex peaks, and rarely involve the sheet metal parts with both concave peaks and convex peaks. However, with the deepening of the research for the CNC incremental sheet metal forming technology, the forming of the multi-peak sheet metal parts with both concave peaks and convex peaks will become a hot research topic. Compared to 3-axis CNC incremental forming, 5-axis CNC incremental forming can extrude the blank in any desired direction because its extruding tool has even more freedom and is more suitable for the forming of the multi-peaks sheet metal parts. In this paper, 5-axis CNC incremental forming path planning and generation method based on STL model has been proposed for the sheet metal parts with both concave peaks and convex peaks. The forming path planning scheme and the algorithms for the cutter location point calculation, forming path planning and extruding tool posture calculation are also given, which are necessary for 5-axis CNC incremental forming path generation for the sheet metal part with both concave peaks and convex peaks. The case study shows that the proposed method can automatically generate smooth and continuous 5-axis CNC incremental toolpath and runs steadily and reliably.