The invention discloses a rail straightening machine with an automatic cleaning function. The rail straightening machine comprises a water tank. A first water inlet pipe is fixedly connected with the left side of the water tank, a first water outlet pipe is arranged on the right side of the water tank, a first pipeline is fixedly connected with one end, far away from the water tank, of the first water outlet pipe, and a second water inlet pipe is fixedly connected with one end, far away from the first water outlet pipe, of the first pipeline. According to the rail straightening machine with the automatic cleaning function, a brush roller and a water gun are arranged inside the rail straightening machine, scraps and sundries on a track and a working device inside the rail straightening machine can be removed, and therefore the effect that the internal scraps and the sundries are removed automatically is achieved; the number of leakage holes is not less than four, the leakage amount in unit time is increased by adding the leakage holes, and therefore the effect of rapid leakage after cleaning is conducted by the water gun is achieved; and dust-proof cotton is arranged below a filter screen, partial scraps and sundries are too small to be filtered by the filter screen, and the filtering effect of the dust-proof cotton is better, and therefore the double-filtering effect is achieved.