Abstract: 1.5kg the Oxytropis Kansuensis powder was extracted by hot water and the liquid was extracted with butanol. Then its adjusted pH to 7.0 and reclaimed butanol. The residue was mixed with silicon dioxide that was extracted with chloroform to remove minimum polarity impurity. In the end, the residue was extracted by ammoniac chloroform, collected ammoniac chloroform phase, vaporized the solvent, sublimated the residue and obtained 7.5mg white needles crystal. The crystal was detected by TLC, which appeared the same dot shape, color and Rf as the standard swainsonine. The chemical structures were identified as swainsonine by means of MP and IR, MS, 1HNMR, 13CNMR..