Time monitoring method and device

The present invention discloses a time monitoring method and a device. The method comprises a step of obtaining a reference time which is the time obtained by a satellite, wherein the time monitoring precision of equipment to be tested is better than 10ms, a step of calculating the deviation of the time of the equipment to be tested and the reference time, a step of judging whether the deviation satisfies a preset condition or not, and a step of determining that the time synchronization state of the equipment to be tested satisfies a working need if the deviation satisfies the preset condition. Through the method and the device, higher time monitoring precision can be provided for a power system.