In order toinvestigate the sensing principle of the sensorless fault diagnosis method used in the fault of the wind turbine drive system, a double-fed induction generator prototype has been built in the environment of SIMULINK. A theoretical analysis for the fault of the wind generator transmission system is used in the response process of the generator stator current. An appropriative simulation test rig for the wind turbine group is established for broken teeth fault simulation and verification of the drive train system. The frequency and amplitude modulation methods of Hilbert transformation are used to analyze the results collected from the simulation experiments. The experimental results indicate that the current in the stator mainly reacts to the torque or velocity fluctuation of the drive train system. Therefore, it is feasible for this approach to be used in wind turbine drive systems of gear teeth broken fault monitoring and diagnosis.