Since the traditional processing technique can no longer meet the requirements of the manufacturing of piston pin hole with special line, a noncircular piston pin hole boring system was proposed, and the corresponding processing and forming principle was analyzed. Based on the principles, a high speed rotation micro feed system was studied and developed. The result shows that the problem of precision machining of piston pin hole with complex lines is solved by using the noncircular piston pin hole boring system, and the center of gravity of the deformable body can keep permanent at radial direction during the deformation process, which insures dynamic balance of the boring system during the high speed rotation boring process of the piston hole. Meanwhile, the surface finish and the appearance of the piston pin hole are highly improved as well as its microshape.