To accurately grasp the cause of HPLC module communication fault in low-voltage mixed loading station area, improve the success rate of data acquisition, a condition monitoring device of smart meter communication module based on high-speed power line carrier (HPLC) technology is designed. The device is installed between the HPLC communication module and the smart meter or concentrator, which automatically monitors the operation status information, communication message information and network noise information of communication modules from different manufacturers in real time through the carrier wave, the information carrying the unified time scale of the whole network is written into the nonvolatile memory by the device in real time, the software automatically parses storage log and identifies the cause of fault through the process. The device is used in two abnormal stations to accurately locate the cause of network fault and improve acquisition success rate, which verifies its practicability.