Black jacket pipe insulation tubes including spiral steel pipe, straight seam steel pipe and seamless steel pipe. Outer layer of black polyethylene material called black jacket pipe insulation. With a high-pressure foaming machine in a cavity between the pipe and the outer protective layer forming the one-time injection of the stock solution of rigid polyurethane foam is made, and then the surface of the polyethylene pipe be processed, forming the outermost layer of the protective layer. Polyethylene shell buried insulating pipe high density polyethylene pipe insulation Buried prefabricated pipe insulation from the transmission medium pipe, polyurethane rigid foam insulation layer and the high density Polyethylene outer tube closely together, buried insulating pipe is mainly used in urban central heating pipe network, oil pipelines, water pipelines and producing alpine region industrial pipeline project. Because polyurethane rigid foam insulation layer tightly bonded steel skin, cut off from the air and water infiltration, can play a good antiseptic effect. Meanwhile foam pipe insulation jacket black holes are closed, water absorption is very small. High-density polyethylene shell, fiberglass shell have good anti-corrosion, insulation and mechanical properties.