Aiming at the problems such as high failure rate, unable to perform state detection, difficult diagnosis of failure mode existing in optical measurement Sensor in HVDC, a state detection technology of the Sensor is proposed. Based on this technology, a dynamic accelerated aging test is carried out in which the Sensor is extracted by independent factor variables such as input voltage, temperature, laser input power, operating years, etc., and its failure mode and failure mechanism are comprehensively analyzed. Finally, it is found that temperature and laser input power are the main factors affecting the operation state of the Sensor, the temperature should not be higher than 30°C and the laser input power should not be greater than 1.2W.