Abstract: β -cyclodextrin-modified membrane was applied in the chiral separation of 1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline(Salsolinol). From the results of HPLC,it was observed that β -cyclodextrin-modified membrane possess the ability of chiral discrimination to the Sal. Through one time diosmosis experiment of membrane circulation, the proportion of Sal changed from 0.87 to 1.55. Gaussian 98 software was used to study the difference of interaction energies between R,S-Sal with β -CD. Calculation were carried out in order to study the relevant mechanism.