Creepage distance of rod composite insulator is an important concern in its quality control. A new method based on machine vision for measuring creepage distance of composite rod insulator is proposed in this paper. Firstly, the image acquisition platform of rod composite insulator is designed, and its axial continuous images are obtained. The SIFT algorithm is used to splice the obtained continuous images, and the Canny edge detection algorithm is used to build the recognition model to realize the automatic measurement of the creepage distance of the rod suspension composite insulator. The test shows that the standard deviation of repeated measurement of image measurement method is about 5% ~ 12% of that of traditional method, and its measurement efficiency is more than 6 times higher than that of traditional method. The accurate and efficient measurement of creepage distance of rod composite insulator is realized.