Aimed at the problem of online detection of continuous slabs surface defect at high temperature, The CCD shutter control model was established using machine vision technology and equipment at high temperature states. The default clustering algorithm was provided. The CCD imaging equipment with dual cool modes of water and air was selected to ensure continuous work at high temperature conditions. The slab width of 3 000 mm can be detected, and the system can effectively restrain the influence of noise signals brought by oscillation marks on the surface of slabs and realize monitoring and clustering of the slab surface default.