To study the deformation performance of composite beam in whole structure subjected to fire,we have carried out two fire experiments of composite beams considering different working conditions in whole structure.The furnace temperature and the temperature of different points in the same section were measured,as well as the vertical deformations at different sections were detected during the experiment.The results showed that:in the fire tests,the composite beams across the same section had a big temperature gradient,which generated thermal stress.However the composite beams couldn’t deform freely because of adjacent components,the vertical deformation of composite beam began to recover in the warming phase and was up-ward finally;The fire behaviors of different composite beams in whole structure was different.Exposed com-posite beam in whole structure shows the good fire resistance.