Abstract: Objective: To establish moderate to severe intracerebral hemorrhage models by injecting type Ⅳ collagenase and heparin into the caudate putamen nuclei of rats.Methods: A total of 66 SD rats were randomly divided into Ⅳ collagenase 0.4 U + heparin 4 U injection group (group A,12 rats),Ⅳ collagenase 0.6 U + heparin 4 U injection group (group,B 42 rats) and Ⅳ collagenase 0.8 U+heparin 4 U injection group (group C,12 rats).The neurological behavior scores of the rats in group A and group C were assessed at 24 and 72 hour after the injection,and those of group B were assessed at 4,12,24,48,72 hour,5 and 7days after the injection.The volume of hematoma and edema was detected by multimedia pathological imaging analysis system.Results: The scores of neurological behavior,the volume of hematoma and edema had obvious difference among the three groups (P<0.01).The hematoma in group A was small and diffused,the edema strip was narrow,and the neurological deficit was light compared with those of group B and C.However,the mortality after injection was 37% in group C,which was much higher than that in the other two groups.Conclusions: Intracerebral hemorrhage models can be established by injecting 0.6 U Ⅳ collagenase and 4 U heparin into the caudate putamen nuclei of rats.The models have obvious neurological deficits and a high persistence,which may be used for the study of intracerebral hemorrhage.