In order to solve the defects of single calculation direction, inaccurate positioning and poor edge connectivity in traditional Sobel operator image edge detection, this paper proposes an image edge detection algorithm that combines Butterworth high-pass fil- tering and improved Sobel operator, and uses the combination of the two techniques to perform edge detection and feature extraction on images. Firstly, the image is pre-processed by the Butterworth high-pass filter, then the improved Sobel operator that adds six - direction templates is used to the traditional Sobel operator for edge detection. Through experimental simulation, compared with the traditional algorithm, this algorithm has the following advantages: prominent edge, good connectivity, low sensitivity to noise, high positioning accuracy.