Referring to the experimental conditions of a 1.5MW wind turbine gearbox, the simulation is carried out considering the inside and outside dynamic excitation based on the ADAMS platform. Through the debugging of relevant parameters, it is found that the damping coefficient of the supporting rigid body has great influence on the simulation results. In the case of 0.1, the amplitude error of the simulation results and the experimental data at the test point MP1 in the time domain can be controlled within 19.3%, and the main frequency distribution in the power spectrum is much the same. It shows the simulation model after tuning parameter can be exact. Then, the broken tooth fault is implanted in the simulation model and the vibration signals at the measured point are analyzed synthetically in time domain characteristics and Hilbert demodulation. The results are consistent with the theoretic description, which further verify the accuracy of the model. At the same time, it can also be proved that the simulation model and method can play a certain role in the research of vibration characteristics and fault signals of wind turbine gearbox.