Abstract: In order to investigate effects of cooling rate on phase transition of hot stamping steel BR1500HS, dynamic continuous cooling transformation (CCT) behaviors of the steel were simulated on Gleeble-1500 thermo-mechanical simulator assisted by Origin software. And microstructure observation and micro-hardness test were carried out as well. The results show that the transformation of pearlite, bainite and martensite occured in the continuous cooling process. The ferrite and pearlitic could be obtained with the cooling rates of 0.5-1 ℃·s-1. The microstructure was bainite with the cooling rate of 5 ℃·s-1. And the cooling rates was higher than 5 ℃·s-1, martensite transformation also started. Only the martensite appeared when the cooling rate was greater than 20 ℃·s-1.