The long-span steel structure is usually used for the stadium, exhibition hall, airports, railway stations and other buildings, and these structures often have an intensive staff, stored supplies are relevant to people's livelihood and so on. If these buildings collapse under the fire, it may cause heavy casualties and property losses, so it’s necessary to make a further research on its fire resistance performance. In this paper, make a fire scenario simulation to the Qingdao North Station main station by using fire simulation software FDS, in order to be sure the increased temperature of components. Then calculate stress of components under the most unfavorable fire temperature with finite element software "Midas" to make sure those components which need a fire protection. Finally, according to the analysis results to determine fire protection scheme, reduce unnecessary waste or local protection can not reach the requirements. This method of fire protection in the paper can provide reference for similar projects.