Through boring distortion simulation and boring trajectory analysis for automobile engine piston hole,a process method was presented in which position change factor and feed speed change factor were used to make the feed rate gradually decease and then increase to original value. Thus the deformation in corresponding positions of the piston bore was controlled. At the same time,the level of the tool path intensity was changed, thereby the shape was amended. So the cylinder hole size precision, the roundness and the cylindricity ,the quality of the plateau honing net vein are improved.