The application discloses a method for diagnosing the mechanical state characteristics of the on-load tap changer of a transformer, which includes the following steps: using a vibration probe to collect a vibration signal generated by the on-load tap changer of a transformer in the operation process; de-noising the vibration signal to get a vibration waveform; intercepting part of the vibration waveform through a short-time energy method, and obtaining the vibration waveform in the switching process; extracting a waveform characteristic value from the vibration waveform in the switching process; and using a RVM classification model to carry out fault diagnosis according to the waveform characteristic value. Through the method, the problems such as long inspection cycle, heavy workload andwaste of manpower and material resources caused by regular inspection and troubleshooting are solved, sudden failure is reduced, and safe and stable operation of transformers is ensured. The application further discloses a device for diagnosing the mechanical state characteristics of the on-load tap changer of a transformer, a piece of equipment and a computer readable storage medium, which all have the beneficial effects.