The invention provides a high-voltage electrical equipment defect detection method and device and terminal equipment. The method comprises the following steps: obtaining a first image of to-be-detected electrical equipment, and extracting a target image in the first image; performing color space conversion and image segmentation on the target image to obtain at least one segmented image; extracting an intersection image of all segmented images, and carrying out morphological filtering on the intersection image; and extracting a target defect area in the intersection image subjected to morphological filtering, inputting the target defect area into a preset defect detection model, and determining the defect type of the target defect area. According to the high-voltage electrical equipment defect detection method and device and the terminal equipment provided by the invention, the defect detection precision of the high-voltage electrical equipment can be effectively improved.