Objective:The purpose of our experiment was to use CT to observe the opening of BBB at the early stage of severely scalded rabbits. Methods:Healthy male New Zealand white rabbits were used to establish 30% and 50% TBSA Ⅲ?scalded model. Using high resolution spiral CT (SCT), the brain parenchyma were observed when plain CT scan and contrast-enhanced CT were performed. Results:CT image changes were found in 4 cases at 6 hour after scald of 30% TBSA Ⅲ?scalded rabbits, while CT image changes were found in all cases at 6 hour after scald of 50% TBSA Ⅲ?scalded rabbits. Conclusion:The larger TBSA is Ⅲ?scalded, the earlier BBB is opening . BBB of 50% TBSA Ⅲ?scalded rabbits are wider than that of 30% TBSA Ⅲ?scalded rabbits