In order to study on the effect of flocking PVC tube on the prevention of crystallization of tunnel drainage pipe.Through the heat treatment on the inner wall of PVC tube, the flocking film smooth side close to the inner wall of the PVC pipe, selection of villus length were 0.4mm and 0.8mm, in two different water conditions, compared with common PVC pipe, 0.4mm and 0.8mm flocking PVC crystal change regulation.The crystallization of the villi was scanned by electron microscope and the bond form between the crystal and the villi was analyzed. The results show that with the increase of time, flocking PVC tube crystal weight was first increased and then decreased or stable trend, while the ordinary PVC crystal tube weight increases slowly; for ordinary PVC tube, the flow speed or larger water pressure pipe wall is not easy attachment of crystalline material, for flocking PVC tube in terms of the crystals attached to the degree of difficulty and villus length are closely related. It is concluded that the flocking PVC pipe plays a certain role in removing the crystallization of the tunnel drainpipe. The length of the villi should be selected according to the flow velocity or the size of the water pressure, so as to give full play to the effect of villous crystallization.