Doubly fed induction generator has been widely used in wind power industry. Compared with electrical failure, mechanical failure in practical engineering operation in particular can not be ignored, and are mostly associated with the air gap eccentricity, whether the rotor rigidity or insufficient bearing wear or installation error, will cause the air gap eccentricity, and even burning motor, air gap eccentric fault diagnosis of wind turbine. So it is very important accurate and efficient. This paper first introduces the failure mechanism of double fed asynchronous wind generator air gap eccentric fault diagnosis method, related to the current key classification described finally in the future, the doubly fed induction wind generator air gap eccentric fault diagnosis method of the development trend and direction.