The purpose of the present invention is to solve the existing problem that it is not easy to directly detect the flatness of the board, and discloses a rapid detection device for the surface flatness used in the processing of resin boards, including a detection mechanism, a bottom plate, a support frame, and a guide frame , connecting rod, net cylinder, adsorption layer, switch, connecting frame, connecting plate, installation rod, first motor, roller, cleaning layer, water pump, first rotating drum, first gear, first connecting ring, first rotating shaft, A first positioning rod, a coil spring, a slide bar, a push plate, a chain, a second gear, a second connecting ring, a second rotating shaft and a second tumbler. The invention rationally uses the net tube to smear colored liquid on the surface of the board, and then presents the imprint of the board through the white paper on the connecting belt, so that the flatness of the surface of the board can be intuitively known, and it is convenient, fast and intuitive to find defects on the surface of the board, and the design is reasonable , easy to operate, in line with the needs of the plate flatness testing field.