Abstract: Line loss in low-voltage distribution networks directly affects both power utilization efficiency and the economic performance of power grid enterprises, while traditional monitoring and management approaches suffer from limitations in real-time capability, granularity, and communication reliability. Power line carrier (PLC) communication, which enables simultaneous transmission of electricity and information through power lines, offers advantages such as low wiring cost, wide coverage, and strong real-time performance. This study introduces PLC technology to construct a low-voltage line loss state estimation model and a sensitivity-based optimization control method, and further proposes a monitoring-evaluation-optimization framework integrating real-time data. Validation on an actual distribution network demonstrates that the proposed method significantly reduces line loss rates, shortens response times, and enhances anomaly detection accuracy, thus providing an effective pathway for refined low-voltage line loss management.