Locomotive hook buffer device working state monitoring device and monitoring method and locomotive

The invention provides a device and method for monitoring the working state of a coupler buffer device of a locomotive and the locomotive, and the device comprises an induction patch which is arranged on the coupler buffer device; the photoelectric range finder is arranged on the locomotive body of the locomotive, and the photoelectric range finder is configured to obtain the position of the induction patch; when the locomotive is in a static state, the photoelectric range finder outputs standard position information of the sensing patch; when the locomotive is in a running state, the photoelectric range finder outputs dynamic position information of the sensing patch; the data processing module is arranged on the locomotive, the data processing module is connected with the photoelectric range finder, and the data processing module is configured to obtain the standard position information and the dynamic position information and output displacement information of the sensing patch according to the standard po