Objective:To study the effects of a new ATP-sensitive potassium channel opener, iptakalim(IPT), on the mRNA and protein expression of vascular endothelial growth factor(VEGF) in the pulmonary artery of rats with hypoxic pulmonary hypertension (HPH). Methods:Thirty-six Sprague-Dawley(SD) male rats were randomly divided into three equal groups:the control group and hypoxic group were given 5 ml/(kg·d) 0.9% sodium chloride,ig; the treated group were given 1.5 mg/(kg·d)] IPT,ig. excepting the first group, the other two groups were put into hypoxic and normobaric chamber[(10.0 ± 0.5)%O2, 8 h/day and 6 day/week] to establish a chronic hypoxic model. After four weeks, the mean pulmonary arterial pressure(mPAP), right ventricle/left ventricle and septum[RV/(LV+S)] were measured. RT-PCR and Western-blot were performed to analyze the mRNA and protein level of VEGF in the main pulmonary artery. Result:①The levels of mPAP and RV/(LV+S) were significantly higher in the hypoxic group than those in the control group(P < 0.01). Iptakalim 1.5 mg/(kg·d) decreased the levels of mPAP and RV/(LV+S)(P < 0.01).②The mRNA and protein levels of VEGF in the hypoxic group were significantly higher than those in the control group(P < 0.01). The trented group significantly decreased VEGF mRNA and protein expression compared with those in the hypoxic group(P < 0.01). There were no differences in VEGF mRNA and protein levels between the control group and the treated group(P > 0.05). Conclusion:IPT 1.5 mg/(kg·d) remarkably inhibited the levels of VEGF mRNA and protein expression compared with the hypoxic group.Iptakalim is a promising candidate for the treatment of hypoxic pulmonary hypertension.