Abstract: Welding technique is the main method used for joining engineering plastic pipe and directly influences the application of enginee-ring plastic pipe.It is very important to study the basic mechanical beha-viors of welded joints at different temperature.So the basic mechanical behaviors of high-density polyethylene (HDPE) electro-fusion welded joint at different temperature were studied by using different specimen designed in this paper.The results showed that the bearing capacity of weld is higher than that of pipe and socket materials at room temperature.In order to get the shear strength of electro-fusion welded joint,the effective bond length was reduced by cutting artificial groove through the socket.The effective bond length of welded joint to get the shear strength is decreased with temperature decreasing.And the shear strength increased with the decreasing of temperature.The sensibility to sharp notch of HDPE material increased with the decreasing.of temperature.