With the improving requirements of the dynamic quality of transmission system, only the eigensensitivities analysis could not satisfying the requirements of dynamic characteristics about transmission system of vehicle. It’s need to turn to response sensitivity research to find guideline for reduce vibration of vehicle transmission system in designing stage. This paper studies the sensitivities of dynamic response with respect to design parameters (such as shaft torsional stiffness, moment of inertia, transmission errors of gear pairs, et al.) The lateral-torsional coupling dynamic model which adopting engine as input source is built up by lumped parameter method. The sensitivity equations are derived from dynamic equations which containing nonlinear terms (such as time-varying mesh stiffness, backlash of gear pairs, mass eccentricity, transmission error et al.). The relative sensitivity of dynamic response with respect to design parameters which then turning into relative sensitivity of force/torque with respect to design parameters are acquired from numerical simulation method. The results of the relative response sensitivities give the theoretical basis of next works which containing dynamic modification, model updating, parameter optimization and so on.