In order to explore the fire-resistant properties of the steel staggered truss framing system (SSTFS),a numerical simulation study of the whole elasto-plastic structural response process of SSTFS subjected to the standard fire curve was conducted with the finite element method by using a plane staggered truss structure model.The evolution of the internal forces and displacements with temperature from the start of fire exposure to the complete failure of whole structure was investigated.The influences of variables like fire mode,fire location and mechanical load level were presented.The results indicate that under fire the collaborative relationship of components leads to the obvious internal force redistribution of the truss members exposed to fire.The plastic deformation has been developed through a longer process.The influences of fire on the whole structure are constrained in local areas.The SSTFS shows a good fire-resistant performance.And there are mainly two fire modes for SSTFS,namely a fire breaking out in the truss floors and in the open floors which leads to significantly different responses for the structures.For those cases proposed in this paper reasonably designed based on the loads at room temperature,when the truss layers are exposed to fire,yield of the mid span of the top chord occurs firstly,but when the open layers are in fire,the external columns are the first components to yield.And the limiting temperature for the complete failure of the structure is slightly higher for the former than the latter.