Objectives：To investigate the collocation and expression variations of aquporin4（AQP4） and inward rectifying potassium channel 4.1（Kir4.1） in astrocytoma of different pathological grades in order to discuss the pathomechanism of proliferation and growth in astrocytoma. Methods：Fifty astrocytoma samples of different pathologic grades were obtained and the relative normal brain tissues contributed to controls. Expression and collocation of AQP4 and Kir4.1 were detected by HE staining，laser scanning confocal mi－croscopy technology and Western blot. Results：Uncomplete collocation of AQP4 and Kir4.1 was present in astrocytoma. Expression of Kir4.1 at protein level was increased along with the ascending pathologic grade. However，expression of AQP4 at protein level was decreased in low-grade astrocytoma and was increased in high-grade astrocytoma. Conclusions：Uncomplete collocation of AQP4 and Kir4.1 is present in astrocytoma. Protein levels of AQP4 and Kir4.1 are correlated with pathological grade of astrocytoma and the vari－ations of AQP4 and Kir4.1 are different. These data suggest that AQP4 and Kir4.1 respectively play different roles in maintaining water and ionic balance.