Abstract: The steam sootblower is a critical piece of equipment in coal-fired power plant boilers, as its operational status directly determines the heat exchange efficiency of the heated surfaces and the energy consumption level of the unit. Its internal leakage faults are characterized by strong concealment and significant difficulty in detection, posing a serious threat to the stable operation of the unit. This study focuses on the internal leakage monitoring system of a steam sootblower in operation at a 350MW thermal power plant. It outlines the working principles of the system and, based on typical issues encountered during field operation—such as hardware failures, data anomalies, frequent false alarms, and maintenance inconvenience—proposes maintenance measures and optimization solutions to address design shortcomings. The findings can provide engineering references for the design and operation of similar steam sootblower internal leakage monitoring systems.