Objective To study penumbra of perihematoma and the time window in rat model of intracerebral hemorrhage.Methods We used coagulated autologous blood to establish the rat model of intracerebral hemorrhage and employed TTC and HE staining to identify normal tissue、ischemic tissue、and necrotic foci.The ischemic scope and necrotic scope were analyzed quantitatively by image analysis technique.Furthermore,the time window of perihematoma penumbra area was determined by statistical analysis of perihematoma penumbra area at different time groups.Results It suggested that penumbra index would gradually reduce with the increase of post hemorrhage time according to groups of 2h、3h、4h and 6h in rat model of intracerebral hemorrhage,the penumbra index was significantly lower in 6h group than in 2h and 3h groups(P<0.01).Conclusions There was a penumbra round the hematoma,the time windows of penumbra was 4 hours.