In this paper the molecular structure,properties and the actire groups in the molecules for epoxy powder coating,adhesive and PE used in the 3PE anticorrosion material for bonding steel pipes were introduced.The reaction process of epoxy powder coation and adhesive and the fusing bonding process of adhesive and PE were discussed.The mechanism of forming a whole from above-mentioned three layers of the 3PE anticorrosion material and resulting excellent performance was approached.