The invention belongs to the technical field of aluminum alloy formwork manufacturing, and discloses a building formwork decoration method, which includes the following steps: S1, making an installation drawing, splitting the layout installation drawing according to the coded general drawing according to the house type; S2, stair decoration, Decorate the stair formwork according to the above-mentioned decoration installation diagram, and the stair formwork adopts a half-decoration method. Compared with the related technology, the present invention adopts the method of laying out the parts on the ground. After each part is arranged, the completeness of the parts is checked on the ground, and the design, processing and assembly problems are checked and rectified. After the problem is rectified, it will be coded and packaged according to the position of the placement. Beneficial effects of the present invention: no actual pre-installation is required, walls, buildings, beams, stairs, windows and other parts can be placed on the ground, which reduces the workload of handling and assembly and disassembly, can reduce labor by 50%, and can verify the formwork on the ground Problems in design, processing, and assembly, and timely rectification at the factory to ensure the quality of aluminum formwork sent to the construction site.