Chamfering tooth crest of spiral bevel gears can effectively relieve stress concentration and reduce noise when spiral bevel gears are meshed, it can also extend service life and increase transmission stability of spiral bevel gears. A model of tools track on chamfering tooth crest of the bull spiral bevel gear was proposed based on analysis of the mechanism for chamfering tooth crest of the bull spiral bevel gear. The NC machine tool and virtual simulation machining models for chamfering the bull spiral bevel gear were carried out with VERICUT. The models of tools track and virtual simulation machining were verified by virtual simulation chamfering tooth crest on one given bull spiral bevel gear with the tools track calculated by Matlab. The measuring results indicate that the model of virtual simulation machining for chamfering the bull spiral bevel gear can meet the design requirements.  