Against to the light weight steel structure irrational problems in practical design process,through analyzing the pillar calculated length formula in portal rigid regulation,the drawbacks of existing steel structure design method were reflected,the urgency of adopting high grade analyzing method was proposed so as to complete steel structure design.

This paper has a valuation on the safety of Design code for the steel structures in according with the subject of National Planning Committee.

In this paper based on engineering example the application of BS in connecting design of steel structure is mainly introduced.