Some drugs exert curative effects intracellularly, but their hydrophilic property prohibits the membrane-penetrating process and thus limits the curative efficacies, although this property guarantee their solubility in aqueous phase. An example is sodium tanshinone II-A sulfonate(DS-201), a derivative of Chinese medical herb Danshen(Salvia miltiorrhiza) which is a BK_(Ca) channel opener and a vasodilator. This study established and optimized a liposome delivery system which could pack and deliver DS-201 into HEK293 cells transfected with BK_(Ca) channels, and DS-201 given this way significantly increased the open probability of BK_(Ca) channel from baseline 0.013 ± 0.004 to 0.036 ± 0.011 at +40 m V membrane potential(P 0.05) in single-channel attached study, and also increased the current density from baseline23.2 ± 4.4 to 66.0 ± 15.2 p A/p F at +40 m V membrane potential(P 0.05), compared with the direct extracellular administration of this drug. Moreover, showing a *60 %inhibition of the PE or PGF2 a induced vascular constriction, the DS-201 liposomes did posses significantly enhanced vasorelaxant effect on rat mesenteric artery,compared with *20 % inhibition of the directly administration of this drug(P 0.05), suggesting that DS-201 delivered by liposomes significantly improved the drug’s vasorelaxing effect. Taken together, the optimized DS-201 liposomes in our study successfully delivered DS-201 into cells and thus significantly activated BK_(Ca) channels to reverse the contraction induced by PE and PGF2 a, attesting the enhanced bioavailability. Some drugs exert curative effects intracellularly, but their hydrophilic property prohibits the membrane-penetrating process and thus limits the curative efficacies, although this property guarantee their solubility in aqueous phase. An example is sodium tanshinone II-A sulfonate (DS-201), a derivative of Chinese medical herb Danshen (Salvia miltiorrhiza) which is a BK_ (Ca) channel opener and a vasodilator. This study established and optimized a liposome delivery system which could pack and deliver DS-201 into HEK293 cells transfected with BK_ (Ca) channels , and DS-201 given this way significantly increased the open probability of BK_ (Ca) channel from baseline 0.013 ± 0.004 to 0.036 ± 0.011 at +40 m V membrane potential (P 0.05) in single-channel attached study, and also increased the current density from baseline 23.2 ± 4.4 to 66.0 ± 15.2 pA / p F at +40 m V membrane potential (P 0.05), compared with the direct extracellular administration of this drug. inh ibition of the PE or PGF2 a induced vascular constriction, the DS-201 liposomes did posses significantly enhanced vasorelaxant effect on rat mesenteric artery, compared with * 20% inhibition of the directly administration of this drug (P 0.05), suggesting that DS Taken together, the optimized DS-201 liposomes in our study successfully delivered DS-201 into cells and thus significantly activated BK_ (Ca) channels to reverse the contraction induced by PE and PGF2 a - 201 delivered by liposomes significantly improved the drug’s vasorelaxing effect , attesting the enhanced bioavailability.