Objective: To study the vascular smooth muscle relaxation effect and explicit the material base of Gastrodia elata Blume. Method: Tension recording for rat isolated aortic artery was used to study the effect of vascular smooth muscle relaxation. Column chromatography and mass spectrography and nuclear magnetic resonance spectrometry were used to isolate and identify the active compounds of G.elata Blume. Result: G.elata Blume. could significantly inhibit the smooth muscle constriction of isolated aortic artery induced by KCl. Five esterified phenolic compounds(Ⅰ-Ⅴ) were isolated from G.elata Blume

such as p-hydroxybenz aldehyde(Ⅰ); p-hydroxybenzyl methylether(Ⅱ); p-hydroxybenzyl alcohol(Ⅲ); 4

4'-dihydroxydiphenyl methane(Ⅳ); 4

4'-dihydroxydibenzyl ether(Ⅴ). The results showed that the vascular smooth muscle relaxation effects were the result of the role of five compounds. Conclusion: The five esterified phenolic compounds(Ⅰ-Ⅴ) from G.elata Blume. play a combined role for vascular smooth muscle relaxation.