In view of the difficulty and complexity of extracting the information of the tunnel excavation faces during the tunnel construction, this paper uses the image processing method to implement the statistics and analysis of the geological information of the tunnel excavation faces. The study is done with the help of image processing of OpenCV. Firstly, contrast-limited adaptive histogram equalization is applied to improve the image quality and provide a sharp image for the subsequent sharpening process. Then the sharpening operation using Laplace operator is adopted to highlight the edge information. Finally, the edge detection is performed by using Canny operator. The results of edge detection are detected by Hough transform, and the straight line description and statistics of rock formation and joint are generated. The results will generate the geological sketch of the excavation faces. The statistics and analysis of the detected lines will provide technical support for the determination of the grade of surrounding rock and the geological analysis.