Single-pass compression tests were performed to investigate the hot deformation behavior of low-carbon boron microalloyed steel containing three various vanadium contents at 900-1100 ℃ and strain rate of 0.01-10 s-1 using the MMS-300 thermal mechanical simulator.The flow stress curves of investigated steels were obtained under the different deformation conditions,and the effects of the deformation temperature and strain rate on the flow stress were discussed.The characteristic points of flow stress were obtained from the stress dependence of strain hardening rate;the activation energy of investigated steels was determined by the regression analysis;the flow stress constitutive equations were developed;the effect of vanadium content on the flow stress and dynamic recrystallization (DRX) was investigated.The result showed that the flow stress and activation energy (316.5 kJ mo1-1) of the steel containing 0.18 wt％ V were significantly higher than those of the steels with 0.042 wt％ and 0.086 wt％ V,which was related to the increase in solute drag and precipitation effects for higher vanadium content.DRX analysis showed that the addition of vanadium can delay the initiation and the rate of DRX.