Abstract: Chiral separation of tryptophan(Trp) by ultrafiltration using bovine serum albumin (BSA) as the selector realized good separation result.The influence of pH value, temperature, initial concentration of tryptophan and BSA as well as the pressure difference of ultrafiltration on the chiral separation process was examined systematically in the present work.The experimental results showed that the influence of pH and temperature on the process was significant.The mechanism of chiral separation was analyzed qualitatively and the influence of pH and temperature was discussed in view of the conformation of BSA and electric charge of tryptophan in the solution, because pH value and temperature played critical roles in the conformation of BSA and electric charge of tryptophan.