The utility model discloses a power substation main transformer high-altitude operation safety device including a high-altitude connecting member and a safety belt suspension device, the two ends of the high-altitude connecting member are connected with a main transformer low-voltage side bus fixing support, the top end of the safety belt suspension device sleeves on the high-altitude connecting member and the safety belt suspension device can move relative to the high-altitude connecting member, the safety belt suspension device is an insulation device, and the bottom end of the safety belt suspension device is provided with a safety belt installing hole. The high-altitude connecting member is arranged for providing a moving path for the safety belt suspension device, a safety belt is suspended in the safety belt installing hole, the safety belt suspension device is an insulation device, a worker can be reliably protected when the worker works on a main transformer without a scaffold. Therefore, the power substation main transformer high-altitude operation safety device can improve the safety of main transformer high-altitude operation.