Application of plaster board and polyurethane rigid foam board is ideal for building external wall insulation without external insulation. At the same time, polyurethane rigid foam board exerts its advantages. When the same heat preservation effect is achieved, the thin polyurethane rigid foam board has little influence on the room area due to its low heat transfer coefficient. This plasterboard and polyurethane rigid foam board can also be used as moistureproof boards.