The model of helical bevel gear machine tool and its machining coordinates are set up through analyzing the mechanism of machining helical bevel gear and the movement rules and structure of helical bevel gear machine tool. The method to calculate the motion parameters of helical bevel gear machine is proposed and the model of simulation machining on helical bevel gear also is set up. The models of helical bevel gear machine tool and virtual simulation machining on helical bevel gear are verified by the virtual machining on one pair of given helical bevel gears with the motion parameters calculated by MATLAB. Results of virtual machining indicate that the model of virtual machining on helical bevel gear can reach design goal.