Abstract: Objective To establish hypoxia-ischemia(HI) brain damage(HIBD) model in rats and investigate the pathologic change in brain tissue after establishing model at the different time point. It would provide the evidence of diagnosis, therapy and repair in clinic. Methods Sixty Wistar rats were randomly divided into control and experimental group. Then the experimental group was also divided into 5 sub-groups as the different time point (4 h，8 h,12 h, 24 h and 72 h ) after the model established. The HIBD model was established by occluding both common carotid arteries and enforcing hypoxia. The pathologic change of brain tissue was observed. Results The obvious pathologic change of brain tissue in experimental group was observed, but it had diversity in the different sub-groups. It was not evident difference among 4 h，8 h and 72 h sub-groups. But the pathologic change in 12 h and 24 h sub-groups became more serious than that in the other sub-groups. Conclusions HIBD model was established successfully in rats. The pathologic change in brain tissue was diversity after building model at the different time point.

Key words: Hypoxia-ischemia brain damage(HIBD), Model, Pathologic change