The invention discloses an automatic maintenance device and an automatic maintenance method for an emergency generator. The automatic maintenance device comprises an industrial computer, a supervisorycontrol computer, a control module, a timing module, a camera, input equipment, an infrared sensor and the like, the control module is connected with a charging relay, an operation relay of a starting circuit of the emergency generator and a stepping motor of an accelerator of the emergency generator, the charging relay is connected with a transformer, the transformer is connected with a rectifying circuit, and the rectifying circuit is connected with a storage battery of the emergency generator. According to maintenance period, battery voltage value and operation maintenance time, set by theindustrial computer, of the emergency generator, the timing module controls the charging relay, the operation relay and the stepping motor to work via the control module, thus supplementary chargingof the storage battery of the emergency generator and operation maintenance of the emergency generator can be realized, the problems of untimely maintenance and excessive maintenance of the emergencygenerator are solved effectively, and the automatic maintenance device is automatic in operation, perfect in safety precautions and capable of enabling the emergency generator to be available at any time.