The invention relates to the field of farm irrigation and particularly discloses a pipe locking machine for irrigation. The pipe locking machine comprises a cover plate which is provided with a round hole, a driving articulated shaft and a driven articulated shaft, wherein the driving articulated shaft and the driven articulated shaft are respectively fixedly connected with a movable plate; the free ends of the two movable plates are respectively provided with an arc-shaped opening; each movable plate is provided with a flange support frame; the cover plate is also provided with a lathy hole; a crank is arranged at the other end of the driving articulated shaft; the free end of the crank is articulated with a driving connecting rod; a driven connecting rod is arranged at one end of the driven articulated shaft; the driving connecting rod is articulated with the driven connecting rod; the cover plate is provided with a gap for a cable of a diving pump to pass through. During use, the pipe locking machine disclosed by the invention is capable of effectively fixing and supporting a connected water pipe when being used for connecting the next water pipe by the support of the cover plate and the flange support frame which is arranged on the cover plate, is capable of conveniently connecting two segments of water pipes by using a flange and can save both time and labor.