Abstract: In view of the complex actual structure of power transformers, a single data source can only reflect the local characteristics of the transformer and the monitoring data is not intuitive. An online transformer monitoring system based on multiple indicators, such as vibration, current, partial discharge, etc., was designed. Software development was carried out in the Qt programming environment for different monitoring data to realize the visualization of the data and reflect the operating parameter information of the transformer more simply and intuitively. The transformer status evaluation model was built based on the system collected data to monitor the transformer operating status in real time. The experimental results show that the system can perform real-time monitoring of the transformer's operating status and visualize the data, which provides data support for transformer fault diagnosis and is of practical significance.