Abstract: Hot compression tests of Q235 steel were performed using Gleeble-3500 tester.The deformation characters and the evolution of deformation induced transformation ferrite of low carbon steel were studied.The ferrite grain became finer as the deformation temperature was decreased,but mixed grain microstructure appeared when the deformation temperature was below Ar3.As the deformation progressed,ferrite nucleated first at austenite boundaries and then at the ferrite/austenite interface.The ferrite fraction increased as the strain increased up to a limit.The dynamic recrystallization of ferrite occurred at high strain.Isothermal holding after deformation led to an inverse transformation of ferrite and the corsing phenomenon of ferrite grain was observed.