In order to solve the problem of intelligent detection of fittings in aerial photography images, this paper proposed a fittings detection method based on modified SSD in power transmission inspection images.The patrol image is rotated from multiple angles and adaptively tailored to expand the sample to solve the problem of a large number of missed detection caused by the small proportion of fittings in the image.Use the improved IoU to get the default box that is more sensitive to the ground truth scale.Further aiming at fittings is dense in the images, adding effective repulsion loss to the model for dense object detection, improve the detection effect of model for dense occlusion fittings.The experiment is based on the dataset of 11 kinds of fittings including 6934 training object boxes and 1879 test object boxes, the detection accuracy of the fittings using the method in the paper reaches 75.64%, which is 4.73% higher than that using the original SSD model, and the detection box is more suitable for the object.