The utility model relates to clamping element of connector which is applied to connect the plastic pipe and the metal pipe, comprising a plastic sleeve and a metal dead ring. The external wall of the plastic sleeve is provided with a hollow groove, one end of the plastic is provided with a locating element while the other end is in connection with the ring-shaped metal dead ring; the plastic sleeve and the metal dead ring have an axial length when adding up; the length of the plastic sleeve is from the locating surface of one side of the pipe joint to the first worm at the same side; and the length of the metal dead ring is the total length of the worm at the side of the pipe joint, the metal dead ring is arranged at the external position of the concentric sleeve on the worm section. The utility model has the advantages as follow: 1.the metal dead ring is applied to fasten the plastic pipe; 2. The plastic sleeve with the hollow groove is used for accurately and conveniently stabilizing the position of the plastic pipe, the joint and the metal dead ring; 3. the utility model is easy in use so as to increase the quality of pipe joint and the installment efficiency.