The invention provides a check valve and a smoke exhauster. The check valve comprises a valve body. A flue is arranged in the valve body. The valve body is provided with a flue inlet and a flue outlet which are communicated with the flue. The end, close to the flue inlet, of the inner wall face of the flue is provided with vortex cutting ribs. The vortex cutting ribs are arranged on the check valve so as to cut large-size and high-energy vortexes formed by soot flowing out of a centrifugal fan of the smoke exhauster at high speed at the flue inlet of the check valve and a centrifugal fan volute tongue, so that the vortexes are dispersed into small vortexes, small in size and easy to dissipate, and the small vortexes are gradually dissipated when flowing in the flue. Accordingly, the problem of noise or vibration caused when vortexes have too high energy and too large size is avoided, and the smoke exhauster noise is reduced.