The invention relates to a plug and play power equipment protocol changing method and device, and belongs to the technical field of power communication. The method includes: when a protocol needs to be changed, receiving a protocol module changing notice, recording protocol changing time, suspending a corresponding protocol parsing module before protocol changing, and starting a corresponding protocol parsing module after changing; processing cache data of the protocol parsing module before the changing time, and transmitting data after the protocol changing time to the corresponding protocol parsing module after changing for parsing so as to load the whole new protocol parsing module. On the condition that power equipment needs not to stop running, a former protocol module is stopped, the new parsing module is started, and normal running of the whole on-line power communication equipment is guaranteed, so that flexibility when a system updates the protocol module is improved, workload of protocol developers for repeatedly developing the protocol module is relieved, and protocol module utilization rate and updating efficiency are increased.