Abstract: AIM: To study the effects and mechanisms of different potassium channel blockers on rat vascular smooth muscle. METHODS: Isometric tension recording of aorta strip. RESULTS: The EC₅₀ values of BaCl₂,　4-aminopyridine(4-AP), cesium chloride(CsCl) and tetraethylammonium(TEA) to increase tension of rat aorta strips were （0.09±0.08） mmol.L^-1，（6.43±1.75） mmol.L^-1，（7.6±1.92） mmol.L^-1 and (11.5±3.09) mmol.L^-1, respectively. 1，4-piperidine(E-4031), sotalol and glibenclamide did not show any influence on the aorta strip tension. On the other hand, our study demonstrated that E-4031, sotalol and 4-AP can inhibit NE-induced contraction in a dose-dependent manner. CONCLUSION: E-4031, sotalol and glibenclamide showed no effect on blood vessel tension at the normal range of concentration and K+ channel blockers may have different selectivity for heart and blood vessels.