In order to ensure the safe travel of the blind, an obstacle avoidance method combining object detection and binocular stereo vision was proposed to solve the problems of blind path occupation, damage and absence. Firstly, the sidewalk information is collected by binocular camera, and the obstacles on the sidewalk are detected by the improved YOLOv8s model. Then, an improved stereo matching algorithm is used to match the obstacles, which uses FAST algorithm with adaptive threshold to find the feature points on the scale space, and uses least square method to obtain the sub-pixel coordinates of the feature points and reduce the dimension of the feature descriptors. Finally, the two-dimensional pixel coordinates are converted into three-dimensional spatial coordinates by the ideal binocular model, and the depth value of the obstacle is obtained. Experiments show that the obstacle avoidance system can accurately identify the types of obstacles in the range of 10 meters, and the FPS can reach 149.1; when measuring the depth of obstacles, the maximum error is controlled within 5.6%, and the FPS can reach 3.8, which meets the requirements of real-time and distance accuracy required by the blind to avoid obstacles.