The principle of NC incremental sheet metal forming as well as the process planning, experiment of sphere forming are presented. Because the deformation of sheet metal only occurs around the tool head and the deformed region is subjected to shear deformation and thins, and surface area increases. Sheet metal forming stepwise is to lead to the whole sheet metal deformation. According to sine law, a sphere can’t be formed by NC incremental sheet metal forming process in a single process, rather, it must be formed in multi processes. Thus, the two time path process method is presented to form the sphere, and the experiment is made to verify it. A sphere can be formed from a sheet metal in NC incremental forming process by choosing appropriate tool-path planning. The fracture in the forming component can be avoided by these methods. A sphere of uniform wall-thickness can be formed from the truncated cone by NC incremental forming process.