An online camber detection system for rough rolling intermediate slab based on machine vision is developed to solve the problem of poor accuracy or lack of means of camber detection in the rough rolling stage of the domestic hot rolling production line. The system mainly consists of the middleware module, the database module and the detection module. The stable operation of the system in a 1 580 mm hot rolling line in a domestic plant shows that the system could detect the roughing intermediate slab in real time, and obtain the plane shape and the camber value. In addition, the qualitative and quantitive characterization of the camber could be obtained according to the corresponding judgment rules. The camber data measured by this system are compared with the measured data of the center line of the billet and the measured data of the width gauge. The result shows that the test results of the system can reflect the camber value of the intermediate slab in the high precision, which provides accurate plane shape data for the camber control.