Steel pipe inner wall washing gun

The invention discloses a steel pipe inner wall washing gun comprising a sand supplying pipe and a high-pressure water supplying pipe located below the sand supplying pipe, wherein the tail end of the sand supplying pipe is connected with a sand separator; the tail end of the high-pressure water supplying pipe is connected with an injection head; the injection head comprises a plurality of independent injection units; and all the injection units are communicated with the sand separator. The sand supplying pipe and the high-pressure water supplying pipe respectively convey mortar and high-pressure water to the injection units; the mortar and the high-pressure water are mixed in nozzles of the injection units to form a grinding material jet flow which moves at a high speed so as to form a linear injection section; and the impact and the washing of the high-speed grinding material injection flow are used so that scales on the inner wall of a steel pipe can be removed in a continuous, efficient and environment-friendly manner. The sand supplying pipe and the high-pressure water supplying pipe are fixed through a pipe clip assembly and a supporting wheel of the pipe clip assembly is contacted with the inner wall of the steel pipe to support a whole de-scaling gun; the de-scaling gun and the inner wall of the steel pipe are in rolling friction, so that the movement resistance is reduced and no barrier exits when the de-scaling gun and the steel pipe move relatively. Furthermore, the height of the supporting wheel is adjustable so as to adapt to the size of the diameter of the steel pipe to be washed.