Abstract: Objective To study the inhibitory effect of telmisartan on the voltage-dependent potassium channel（Kv1.3）expression in peripheral blood T lymphocytes of patients with hypertension. Methods Thirty Xinjiang Kazakh hypertensive patients without antihypertensive therapy were randomly selected from hypertensive clinic of the First Affiliated Hospital of Xinjiang Medical University from August to December 2012,and the patients were randomly assigned to control,telmisartan or 4-aminopytidine（potassium channel blocker）group（n=10each group,5males and 5females）. Peripheral blood T lymphocytes isolated by magnetic cell sorting were first cultured for activation and proliferation in vitro,and then incubated for 0,24,or 48 hrespectively after telmisartan or 4-aminopytidine treatment. Real-time quantitative PCR（RT-PCR）and Western Blot were used to detect the Kv1.3channel mRNA and protein expression. Results The mRNA and protein expressions of the Kv1.3in T lymphocytes in telmisartan and 4-aminopytidine group were significantly reduced compared to those at the same time points of control group（all P＜0.05）.In T lymphocytes after 24 hand 48htreatment with telmisartan,inhibition rates of Kv1.3mRNA expression were 50.0%,73.5%,and the protein expression were 49.3%,67.9%,respectively.Conclusion Telmisartan could effectively inhibit the Kv1.3potassium channel mRNA and protein expression in T lymphocytes of patients with hypertension in Xinjiang Kazakh.