With the rapid development of buried power cable laying project, higher requirements for cable protection are put forward, the cable protective sleeve is made of PE and high quality steel pipe by sand blasting and shot blasting, dipping or painting, heating and curing. It is the most common type of electrical insulating tube used to protect wires and cables. It is widely used because of its good insulation, high chemical stability, no rusting, no aging and adaptability to harsh environment. Using cable protection casing protection cable can achieve the following advantages: 1, good corrosion resistance, long service life, can be used in the humid, wet saline areas. 2, flame retardant, good heat resistance, can be used at 130 degrees high temperature for a long time without deformation, do not burn in case of fire. 3. High Strength, high stiffness. It does not need to add concrete protective layer to be buried directly under the carriageway and can speed up the construction progress of the cable project. 4. The Cable Protection Bushing, whether it is pipe material or pipe fittings, has certain flexibility and can resist the damage caused by the external heavy pressure and the foundation settlement. 5. It has good anti-interference performance. 6. The inner wall is smooth and does not scratch the cable. The design adopts the socket type connection mode, which is convenient to install and connect. The rubber sealing ring at the joint can not only adapt to the heat expansion and cold contraction, but also prevent the mud and sand from entering.