The launch for vehicle equipped automated mechanical transmission was studied. Based on the torsional vibration parameters of vehicle powertrain, such as inertia, stiffness and damp, 6-DOF model of vehicle powertrain was established. Considering the variable friction coefficient and cushion spring nonlinear compression characteristic of clutch driven plate, it controlled the changing rate of throttle opening, engaging displacement and speed according to the opening of acceleration pedal to keep the constant speed of engine while launching. Through the method of simulation, the launching control method with constant engine speed was proved to be feasible. The clutch output torque and jerk value while launching considering torsional vibration factor of powertrain was obtained. The results of simulation were closer to the reality.