In view of the current high-speed power line carrier technology (HPLC) lack of an effective monitoring system, this paper proposed a design scheme of an HPLC operation monitoring system based on noise decomposition. The system adopts modular design, including signal acquisition, information transmission and noise decomposition. The signal acquisition module adopts capacitive coupling technology, which considers the convenience and accuracy of the system monitoring performance. The information transmission module adopts wireless transmission technology to meet the needs of HPLC channel monitoring. The noise decomposition module completes the decomposition and identification of noise by constructing a feature library, and realizes the quantitative evaluation of on-site noise. The proposed scheme is of technical reference for improving the portability and accuracy of the monitoring system.