Abstract: The expanded polystyrene sheet (EPS) is an energy-saving material for buildings, which has wide use and good practicability. EPS features excellent thermal property, energy-saving and environmental protection etc when it is used for external wall insulation. According to the insulation peeling, cracks of finished coats and poor appearance etc occur frequently in actual projects, it is pointed out that during the construction of EPS external wall insulation, the quality of the project can be insured and the expected technical and economic benefits can be obtained only by paying attention to the quality of the selected materials and the compatibility among the main materials besides enhancing the improvement on construction technology.