The invention discloses a smart inspection device for power grid based on UAV, which belongs to the technical field of UAV inspection. The utility model comprises a body, a flying arm, a propeller, an inspection device and a protective device. The body includes a main body and a lower fixed plate. The main body is fixed on the upper surface of the lower fixed plate by a first screw. The upper surface of the lower fixed plate is provided with a first rotating hole, and several flying arms are rotatably coupled with the first rotating hole. In the present utility model, by setting the flying arm, the flying arm can be freely retracted and can be retracted when it is not in use, saving space and protecting the equipment structure from external force damage. By setting a waterproof cap, rain water can be prevented from entering the body in rainy weather, and high temperature can avoid direct sunlight on the body, so that the equipment can work normally in harsh environments.