This research analyzes an innovative forging mold design for the various bicycle stem. The paper used the rigid-plastic finite element analysis software and structural analysis to investigate the plastic deformation behavior of aluminum alloy A7075 workpiece for forging process. Under various forging conditions, it analyses the effective strain, the effective stress, the temperature changing, surface pressure, mold radius load distribution, stress analysis of billet and mold. Moreover the paper used the Taguchi method combine the algorithm method of artificial neural network to find out the best design parameters. The paper hoped to offer some tolerance um precision forging manufacture knowledge for industry.