To accurately grasp the cause of high-speed power line carrier (HPLC) module communication fault in low-voltage mixed loading station area, improve the success rate of data acquisition, a condition monitoring device of smart electricity meter communication module based on HPLC technology is designed. The device is installed between the HPLC communication module and the smart electricity 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 the success rate of data acquisition, which verifies its practicability through experiments.