In the process of steel structure engineering design, the selection of reasonable steel has a very critical role. It can be said that the task of steel selection is both important and difficult. There are many kinds of steel in China, and it is difficult to choose the most suitable steel for steel structure construction from many steels, and the current steel structure engineering construction design for steel requirements are also high, different steel structure engineering requirements for steel structure strength, deformation and fatigue stress are also different, so there is a certain degree of difficulty in the selection. Therefore, in the design, in order to better play the role of the steel structure, must start from the actual, combined with the specific construction requirements of the scientific selection of steel. In the selection of steel, it is also necessary to scientifically judge its applicability. At present, the span of the building steel structure and the load are relatively large, mainly used in the more complex high-rise steel structure project or large steel structure project. Therefore, the steel must meet the construction needs of the steel structure, be able to withstand high temperatures and vibrations, and be easy to disassemble. This requires the designer to investigate and study before design, and comprehensive analysis, fully consider the suitability of the steel structure, before the design work can be carried out.