Abstract: Based on the principle of gear mesh and hob designing, a method to design an asymmetric involute spur gear was provided and the calculation formula was deducted. The parameter solid model was set up using a calculation example. On the base of the principle of gear manufacture, parametric programs programmed with Visual Basic software and Autolisp program were separately introduced to simulate the envelope process of asymmetric gear manufacture. The result shows this method provides a foundation for new-style asymmetric gear manufacture and experimental study.