The plastic has the characteristics of light weight, corrosion resistance, small thermal conductivity, heat preservation, waterproofing, energy saving, convenient processing and high recycling rate, and is widely used in the construction field. Plastic building materials are also the fourth largest building material after steel, wood and cement. The energy consumption of plastic building materials is low. Plastic water supply pipes have better recovery and recyclability than metal and wood building materials. They can substitute a large amount of steel for wood, and have energy conservation, ecological protection, improvement of living environment, improvement of building function and quality, and reduction of building weight.