EUVI-1 UV imager is a novel corona discharge instrument based on photomultiplier tube (PMT) and ultraviolet technology, which has excellent functions of distance detection for corona discharge in determined region from surface of high voltage equipments and corona characteristics data analysis. It is mainly applied to detect the incipient fault and performance decreasing of high voltage polymer insulators, high voltage cable and other high voltage equipments for saving the great maintenance and repair cost of the high voltage items, minimizing the nonscheduled electricity failure, improving the power distribution reliability, which will bring huge economic benefits as well as social benefits.