Ultra-fine austenite grains with size of 1～3μm were prepared in a Nb-V-Ti steel through repetitive treatment of rapid heating and quenching.A model for the growth kinetics of these ultra-fine austenite grains was successfully created through successive 2 processes,and the activation energy Q for growth was estimated to be about 693.2 kJ/mol,which directly shows the inhibition effect of microalloy elements on the growth of ultra-fine austenite grains. Ultra-fine austenite grains with size 1 to 3 μm were prepared in a Nb-V-Ti steel through repetitive treatment of rapid heating and quenching. A model for the growth kinetics of these ultra-fine austenite grains was successfully created through 2 processes , and the activation energy Q for growth was estimated to be about 693.2 kJ / mol, which directly shows the inhibition effect of microalloy elements on the growth of ultra-fine austenite grains.