Abstract: By using a Gleeble-1500 thermomechanical simulator, the laws of dynamic continuous cooling transformation and microstructure evolution of interstitial free steel (IF steel) produced by TSCR were investigated. It was found that the transformation temperature Ar3 decreases with the cooling rate increasing, which is beneficial to the low-temperature finish rolling and more excellent property of IF steel. The hardness increases with increasing the cooling rate. When the cooling rate rises from 1℃/s to 30℃/s, the HRB value correspondingly increases from 53.43 to 68.3. As a result, the strength improves with increasing the cooling rate.