The “portal frame lightweight building steel structure” mainly comes in two forms: double slope and single slope. Portal frame is not only suitable for light steel, but also includes ordinary steel. The light steel door gauge is only the light steel part of the portal frame structure. Portal light steel is commonly used for steel structures in production workshops, warehouses, and factory buildings. When designing, the first step is to determine the adoption of standards. It cannot be generalized that all door types are made of light steel.