Abstract: A road crack maximum width detection system used binocular visual is designed. A skeleton-based edge corrosion algorithm is proposed, which can be applied to the calculation of the maximum pixel width of various types of cracks. The image acquisition is carried out by the two-eye camera, and the maximum width pixel coordinates obtained are converted to world coordinates, so as to calculate the actual maximum width of the crack. Compared with the traditional method, the detection accuracy of the algorithm is improved by 4.93%,and the speed is increased by nearly 3.2 times. So that the efficiency of the whole crack detection system is greatly improved.