Plastic alloy pipe is made of polyvinyl chloride as the main raw material, applying the synergistic multi-molecule material co-mixing technology, with toughening agent, anti-aging agent and other auxiliary additives, etc., through the division of kneading and with the overall kneading process, after interpenetrating network alloying treatment. Using the principle of mechanical distribution of innovative structural design, the whole structure of the outer square and inner circle once extruded, can be used to replace the steel pipe for the line across the road buried laying projects and ports and harbours, bridges, highways, airports, tunnels and other projects, with significant social benefits. It not only has the good overall performance of the general pipe, but also has a high impact resistance, high toughness, high compressive strength, long service life and other outstanding performance, and the light weight of the pipe, the inner wall is smooth, the friction coefficient is small, easy to put the cable through.