Polyurethane insulation pipes can be used for heating and cooling, and their thermal conductivity is relatively low in insulation materials, so the heat loss of the material can be reduced to a lower limit. The polyurethane foam insulation layer of polyurethane insulation pipe is applied to the anti-corrosion layer of steel pipe by on-site casting or prefabrication, which is simple and easy to use, waterproof, anti-corrosion and aging resistant. Because the closed cell ratio of polyurethane foam is more than 92%