A stereo matching method based on image intensity quantization is revealed. The method includes several steps. Firstly, provide computer an image pair of an object for image intensity quantization of the image pair to get a quantization result. Then according to the quantization result, a first extracted image pair is generated and used to get a first disparity map. A second extracted image pair is generated similarly to get a second disparity map. Next the two disparity maps are compared with each other to get an image error data. When an error contained in the image error data is smaller than or equal to an error threshold value, the computer outputs the second disparity map. Moreover, accuracy of disparity maps is improved by iteration processing. Therefore, the amount of information for processing is minimized and efficiency of data access/transmission is improved.