Abstract: Pipeline three-layer PE corrosion protection is a new technology in pipeline corrosion protection currently. Combined with the three-layer corrosion protection assembly line adopted in Korshan Oil Pipeline, the article analyzes the structure and property of the three-layer coating and compares it with other coatings in corrosion property, process flow, equipment construction, quality control and environmental pollution, etc. Conclusion shows that three-layer PE coating centers all advantages of many kinds of coatings, with excellent properties of viscosity, electrical isolation, water resistance and erosion resistance, and good mechanical strength and toughness. It can be used in various environmental conditions including terrestrial pipeline and offshore pipeline, and introduces the main equipment used in three-layer corrosion protection assembly line at the sametime.