Coated steel pipes are products that use PE (modified polyethylene) for hot-dip molding or EP (epoxy resin) for internal and external coating, and have excellent corrosion resistance. At the same time, the coating itself also has good electrical insulation and will not produce electrical corrosion. Low water absorption rate, high mechanical strength, low friction coefficient, capable of achieving long-term use. It can also effectively prevent damage to plant roots and soil environmental stress. Convenient connection and easy maintenance