A bending-torsion-axial coupled lumped parameter dynamic model of planetary gear and two parallel-axes transmission system with 31 degrees of freedom was established, with considering the factors of time-varying mesh stiffness, mesh damping, and transmission error. First, Runge-Kutta method with variable time step was introduced to solve the dynamic differential equations, and all gear transmission errors were calculated. Then, a wind power gearbox flexible coupling dynamics model with transmission errors was built by using LMS Virtual.Lab, and gearbox bearing reaction forces used as acoustic coupling model boundary conditions were obtained by mode superposition method. Finally, wind power gearbox noise and vibration were predicted by using acoustic finite element method and the results were compared with the test results. Comparison results show that considering the gear dynamic transmission error excitation, the gearbox surface vibration response and radiation noise are in good agreement with the test results.