To quickly and accurately detect rectangles and comprehensively analyze the advantages and disadvantages of existing rectangle detection algorithms, a fast and high-precision rectangle detection algorithm is proposed herein. The proposed algorithm first divides an image into multiple regions of interest using a ring window, then extracts the subpixel contour of the region of interest, divides the subpixel contour into several line segments, and finally uses fuzzy mathematics to analyze the geometric and physical characteristics of the line segments. As a result of the fusion calculations, high-precision detection and positioning of the rectangle are obtained based on the fuzzy fusion assessment. Experimental results show that the detection speed of the proposed algorithm is 7.4 times that of the rectangle detection algorithm based on Hough transform, and the maximum center positioning error is (0.507 pixel, 0.272 pixel). Furthermore, the average length error is 1.034 pixel, the average width error is 1.310 pixel, and the average inclination error is 0.304°. The rectangle can be accurately detected through the proposed algorithm that meets the requirements of fast and high precision in industrial applications and exhibits strong stability.