The utility model provides a pre -buried pipe in water special mould among prefabricated component, is connected fixedly through the bolt of installation in the central through hole with the steel platform truck including the rubber frustum body that has the central through hole, the rubber frustum body. Its tapering of the rubber frustum body be 6 degrees. The lower part center of the rubber frustum body have a bolt and nut mounting hole, the nut is connected with the steel platform truck and is fixed bolt lower extreme and welded nut screw thread threaded connection. The utility model discloses the installation accuracy of mould built -in fitting can be effectively guaranteed, this frock is taken out during the form removal smoothly to precast concrete component appearance quality is good.