A method for predicting the service life of a yaw bearing of a wind turbine generator comprises the following steps: establishing a geometric model, creating a contact pair, applying constraint and load, performing numerical simulation, importing an ANSYS result, setting parameters, calculating the result, establishing the geometric model when the bearing clearance is 0 by using three-dimensional modeling software, inputting the parameters of a model material, setting the unit size, and performing grid division on the model by adopting a sweeping mode. According to the method for predicting the service life of the yaw bearing of the wind turbine generator, the contact stress of the bearing of the wind turbine generator is analyzed and calculated by using ANSYS software through a fatigue life numerical value simulation method, so that the service life of the bearing can be predicted, the prediction accuracy is improved, a worker can conveniently maintain the wind turbine generator, and the influence caused by wind turbine generator faults is reduced.