Objective To compare milrinone （MIN）, Phenoxybenzamine （PHE），and mixture of nitroglycerin and verapamil(NVC) for the prevention and treatment of human radial artery spasm. Methods Residuary radial arteries from 30 patients undergoing coronary artery bypass grafting （CABG） using autologous radial artery from March to September of 2012 in General Hospital of Shenyang Military District were collected. All the artery specimens were cut into 60 vessel rings of 3 mm in width and hanged in the Organ-Bath. Using a random number table，all the vessel rings were divided into 4 groups：PHE group，NVC group，MIN group and blank group （control group）. Firstly，20 vessel rings were used for spasm relaxation experiment with 5 rings in each group. Phenylephrine was added into the Organ-Bath to reach final concentration of 10-3 mol/L in order to cause vessel rings spasm. PHE of 1 mmol/L，NVC of both 30 μmol/L，MIN of 30 μmol/L and Krebs-Ringer’s solution were added respectively into above groups to compare the relaxant effect of these vasodilators on radial artery spasm. Secondly，the other 40 vessel rings were used for spasm prevention experiment with 10 rings in each group. All the 40 vessel rings were dipped in above 4 groups. After 30 minutes，phenylephrine was added to the Organ-Bath to reach final concentration of 10-3 mol/L. Time-dependent constriction of the vessel rings were compared to examine the prevention effect of these vasodilators on radial artery spasm. Results In the spasm relaxation experiment, vessel ring spasm relaxed most quickly in NVC group （P＜ 0.01）. Vessel rings in MIN group relaxed more slowly but steadily （P＜ 0.05）. Vessel rings in PHE group relaxed most slowly （P＜0.01）. And there was no relaxation in the control group. In the spasm prevention experiment，vessel rings in the control group contracted （spasm） 100% immediately after phenylephrine administration. Vessel rings in MIN group contracted immediately after phenylephrine administration too，but slower than the control group（P＜0.01）. Vessel rings in NVC group did not contract right after phenylephrine administration，but the sedentary tension of these vessel rings gradually increased 120 minutes after phenylephrine administration，and vessel ring contraction reached 46.89% 240 minutes after phenylephrine administration. There was no vessel ring contraction in PHE group. Conclusions All the vasodilators in our experiment are effective for the prevention and treatment of radial artery spasm to different degree，but each medication has its own characteristics，vasodilatation result and time-dependent effect. NVC is most effective to dilate radial artery which has been in spasm state, while radial artery pretreated by PHE is least to become spasm after being stimulated.