Mechanical failure is still the main type of failure of high voltage circuit breakers. Timely and accurately diagnosing the mechanical fault of HV circuit breaker is the key to realize the condition maintenance of HV circuit breaker and ensure the safe operation of power grid. This paper introduces the basic situation of the mechanical fault of HV circuit breaker. According to the basic flow of fault diagnosis, the research status and main shortcomings of the mechanical fault diagnosis methods of HV circuit breaker are summarized from three aspects: signal pre-processing, feature extraction, dimensional-reduction screening and fault identification methods. Finally, the key and difficult problems in the field of mechanical fault diagnosis of high voltage circuit breaker are discussed, and the development of diagnosis methods in the future is prospected.