The utility model discloses a hidden fault monitoring system of a transformer station communication device, and relates to the field of communication device monitoring technology, and the technical problem which is solved is to provide convenience for the overhaul of the electric communication device. The system includes a central computer which is arranged in a monitoring center, a plurality of terminal station computers, and a plurality of cameras which are arranged into different transformer stations. The terminal station computer real-timely records a state indicating lamp image of an instation communication device via the camera, and real-timely downloads a communication message of the instation communication device, and then uploads the recorded image, the downloaded communication message, the recorded time point, the download time point to the central computer, and finally the working personnel in the monitoring center find the hidden fault and the reason of the hidden fault based on the image and the data uploaded by terminal station computers. The system provided by the utility model is helpful for a maintainer to carry out the overhaul of a fault device.