The utility model discloses a simple underwater pipe cleaner consisting of a main barrel, a self-locking flange, a quick connector, a bypass pipe unit, a pressure liquid connection unit and an emptying unit, wherein the main barrel consists of a plurality of barrels; a flange is welded between a first barrel and a second barrel; a flange is welded between the second barrel and a third barrel; the flanges and the self-locking flange are fastened by a bolt; the lower part of the third barrel is connected with the quick connector; the self-locking flange and the third barrel are provided with the bypass pipe unit at the side; the upper part of the first barrel is provided with the pressure liquid connection unit; and the side of the first barrel is provided with the emptying unit. The cleaner can realize underwater single-barrel and multi-ball intermittent transmission. A plurality of pipe cleaning balls can be stored to be used for the work of pipe cleaning. The interval time for the transmission of every pipe cleaning ball can be selected by a user. After the work of pipe cleaning is finished, the cleaner can be dismounted and brought back to the land. Therefore, the corrosion of sea water on the cleaner is significantly reduced, and the service life of the pipe cleaner is prolonged. During pipe cleaning, the time for a diver to stay underwater can be shortened, and the safety of operation personnel can be enhanced.