The invention discloses a cotton cleaning machine which comprises a bearing pedestal on a cotton cleaning machine body and a licker-in. A spindle is arranged on the licker-in, the spindle is arranged on the bearing pedestal through an inner bearing and an outer bearing, a protective cover is arranged on the side, close to the licker-in, of the bearing pedestal, an open hole is formed in the center of the protective cover to allow the spindle to penetrate, a discharge opening is formed in the lower portion of the protective cover, protruding pipes concentric with the spindle are arranged on the inner side of the protective cover, hairbrush rings are arranged in the protruding pipes through bearings, and bristles capable of cleaning the spindle are arranged on the inner walls of the hairbrush rings. The cotton cleaning machine has the advantages that dissociative fibers and dust can be prevented from entering the bearing pedestal by the protective cover, impurities can be prevented from entering the bearing pedestal by bearing glands if the impurities or the dissociative fibers enter the protective cover, and therefore the bearings in the bearing pedestal can be further prevented from being influenced by the impurities.