High-density polyethylene direct-buried thermal insulation pipe has the advantages of efficient thermal insulation, waterproof, anti-corrosion, thermal insulation, fire resistance, cold resistance, light weight, high strength, simple and fast construction, and no fear of plant root thorns. It is widely used in urban central heating, warm rooms, cold storage, coal mines, oil pipeline ports, chemical engineering, natural gas pipelines, electric power direct-buried, central air-conditioning pipeline insulation, cable threading Thermal insulation and cold insulation engineering in steam insulation pipeline and other industries. The polyurethane direct-buried insulation pipe is suitable for the thermal insulation and cold insulation engineering of various media in the range of - 50 ° C-1 50 ° C. Prefabricated direct-buried thermal insulation pipe not only has advanced technology and practical performance that are incomparable with traditional trench and overhead pipeline, but also has significant social and economic benefits, and is also a powerful measure for heating and energy conservation.