In order to analyze the influence of internal excitation factors on tooth surface vibration of cylindrical herringbone gear,the herringbone gear vibration model is established considering time-varying meshing stiffness excitation,corner mesh impact force excitation,and the backlash influence. The influences of internal excitation factors on tooth surface vibration of cylindrical herringbone gear are calculated according to different load and speed conditions. Taking the one-stage herringbone gear transmission system as an example,the simulation results consistently show that meshing stiffness excitation is the main influencing factor on vibration of herringbone gear. The influences of backlash increase with the rotation speeds increase,but decrease with the loads increase. Those influence rules provide a more reasonable design target for the follow-up tooth surface vibration and noise reduction optimization.