Objective：To observe the changes of aquaporin 4（AQP4） polarized expression in the brain following intracerebral hemor－rhage（ICH），and to explore its roles in the brain edema following ICH. Methods：Rats were randomly divided into ICH group and sham group；and autologous blood was injected into the right caudate nucleus to establish ICH model in rats. The hematoma volume was mea－sured by magnetic resonance imaging，the brain water content（BWC） was measured by the wet and dry weight methods，and the po－larized expression of AQP4 was detected by immunofluorescence. Results：On d1 post ICH，the hematoma volume reached the peak，the BWC reached its maximal value（79.769±0.710）%，and the difference between the sham group and the d1 post-ICH group was statistically significant（P=0.000）. In the perihematomal tissue，the polarized expression of AQP4 was lost，and AQP4 was expressed in astrocytic soma. However，in the sham tissue，AQP4 was polarized expressing in astrocytic end-foot membrane. Conclusion：In the per－ihematomal tissue of brain following ICH，the polarized expression of AQP4 is lost，which may contribute to the formation of brain ede－ma following ICH.