Transmission line and equipment corona of transformer station can be used to locate defect and analyze real situation of insulation. A UV imager based on solar blind filter and MCP detector was described. This instrument worked with visible light video camera in the same visual field and high sensitivity detection and location for corona were realized. In order to test the performance of UV imaging detection, high voltage point discharge equipment was used in experiments of different discharge intensities and on-site corona discharge detection. Results showed that the developed UV corona imager could be applied in detecting high voltage corona and locating fault.