This paper systematically discusses the whole theoretical system of steel structure design methods, expounds and comments on various methods of steel frame stability design and their evolution, and systematically summarizes the classification, internal force analysis method and support stability design method of multi-storey and high-rise steel structures, and the judgment method of instability mode of high-rise steel structures. This paper introduces and comments on the important concepts and methods of seismic design of steel structures, introduces the basic theories of important seismic design and the developing seismic design methods of steel structures, especially expounds some important concepts, and introduces the influence of damping, late stiffness, second-order effect and multi-degree-of-freedom system on seismic force. The calculation method of ductile seismic force of steel structure and its supporting seismic design measures are summarized and put forward. On the basis of summary, the classification method of beam, column, plate and lateral force resisting structural system is put forward, and four tables of structural influence coefficient are designed. This paper introduces various classification methods of beam-column connection, and introduces five most commonly used design methods of beam-column connection.