The invention discloses a power transmission and transformation line insulator aerial image fault detection method based on improved YOLOv3. The method comprises the following steps of S1, establishing an insulator data set and an insulator fault data set; s2, performing data enhancement by using modes of rotation, overturning, contrast enhancement and the like; s3, taking YOLOv3 as a basic framework, carrying out model modification pruning operation, and constructing an insulator detection model; s4, establishing a standard YOLOv3-tiny network; s5, carrying out model training on the modifiedYOLOv3 network and the modified YOLOv3-tiny by using the insulator data set and the insulator fault data set; and S6, connecting the two trained models to realize end-to-end rapid detection of the insulator fault. According to the detection method, the insulator in the complex background image can be quickly and accurately identified, the fault area can be positioned and detected, the inspection efficiency is improved, the working intensity of inspection personnel is reduced, and a guarantee is provided for normal operation of a power system.