Abstract: At present, the converter station on-line monitoring systems includ:the on-line monitoring system of converter-transformer, the on-line monitoring system of HGIS/GIS. Because each system has a separate site collection unit and system, so different manufacturers' analysis software, device interfaces and communications protocols often not compatible, the monitoring data can not be shared, leading to on-site installation and commissioning work capacity, operation and maintenance are extremely inconvenient. In order to save the costs of the converter station equipment and maintenance costs, we built a comprehensive on-line monitoring system, it prompted on-line monitoring system from one isolated, stationary systems to the networked, integrated intelligence on-line monitoring system.