Abstract: Influence of different holding time after rolling and deforming temperature on the precipitate behavior of low carbon and high niobium microalloyed steel was studied by heat simulation experiments and TEM analysis.The results show that many Nb(C,N) precipitates could be found in austenite with selecting suitable holding after deformation,then the content of dissoved niobium could be decreased accordingly and the effect of decreasing the phase transformation temperature from austenite to ferrite could be weakened.However,many Nb(C,N) precipitates could be found in ferrite and interphase precipitation could be arised while selecting sutable defoming temperature,so that there is a better influence on the precipitation strengthening.