Abstract: Objective :To study the alterations in the expression of inwardly-rectifying potassiumchannel 4.1 (kir4.1) in human astrocytic tumors and to explore the molecular mechanism of astrocytictumor proliferation and growth. Methods :The tumor tissues of 50 patients with astrocytic tumors wereselected, including 21 cases of glioblastoma, 15 cases of anaplastic astrocytoma and 14 cases of astro-cytoma. The normal brain tissue around the tumor served as a control.Immunohistochemical stainingand Western blot analysis were used to measure the expression of kir4.1 protein. Results :The expres-sion of kir4.1 was significantly increased in tumor tissues compared with the control samples (P<0.05),and the expression of kir4.1 in glioblastoma was much higher than that in astrocytoma and anaplasticastrocytoma. Conclusion :Protein expression of kir4.1 is related to the malignancy of astrocytic tumorsand it is increased in human astrocytic tumors compared to normal controls.