The invention discloses an anti-blocking blow-off pipe. The blow-off pipe comprises an outer pipe body and an inner pipe body; the inner pipe body is sleeved with the outer pipe body; an elastic mechanism is arranged between the outer part of the inner pipe body and the outer pipe body; a spiral bulge is arranged on the inner wall of the inner pipe body; a main sleeve is mounted on the inner sideof the top water inlet end of the outer pipe body in a threaded manner; a pipe opening insert is mounted on the inner side of the top end of the inner pipe body in a threaded manner; and a water guidepiece is mounted on the inner side of a casing pipe of the main sleeve in a threaded manner. According to the blow-off pipe, the outer pipe body and the inner pipe body are arranged, the elastic mechanism is arranged between the outer pipe body and the inner pipe body, under cooperation with the spiral bulge arranged on the inner wall of the inner pipe body as well as the main sleeve, the pipe opening insert and the water guide piece which are mounted at the pipe opening, during sewage drainage of the blow-off pipe, sewage flows inside the inner pipe body to produce the centrifugal force, then under cooperation with the arranged elastic mechanism, shocks are produced by the inner pipe body, solid particles in the sewage are favorably discharged from the inside of the pipe and are prevented from being attached to the inside of the pipe, and thus the anti-blocking effect is realized.