Abstract: A highly potent beta-adrenergic irreversible antagonist——Bromoacetylalprenololmenthane (BAlpM)was synthesized by a Six step method with phenol and allychloride as the starting materials. Some improvement on purification of the product was described. The final product is identified by melting point, elemental analysis, UV and IR spectral analysis and mass spetrometry as well as β-adrenergic receptor bindingassays. ¹²⁵I±IODOPINDOLOL binding assay of mouse lung cell membrane preparations treated with BAlpM in vitro or in vivo showed that there was a dosedependant decrease in the density of specific binding sites with no change in the Kd values. This result confirms that BAlpM is a β-adrenergic irreversible antagonist.