Abstract: In order to accurately predict the effect of chiral separation, this work obtained several complexation constants from a large number of singular tryptophan (Trp) enantiomer experiments and compared three models of complexation mechanism of tryptophan to bovine serum albumin (BSA).In the pH range from 7 to 12, the complexation mechanism was a competitive binding of D- and L-tryptophan on a single site.Complexation constants (KD and KL) varied significantly by changing pH in the solution and the variation of KD and KL was caused by the change of conformation of BSA and electric charge characteristics of Trp.The model could well predict the concentration of D-tryptophan in the permeated solution and separation factor.The calculation equation of complexation constants was given by regressing experimental data to a certain function.