Abstract: Resolution of D,L-phenylalanine by ligand exchange extraction, first using N-carbobenzyloxy-L-amino acid as chiral ligand, was studied in this paper. Factors including organic solvent, chiral complex and complex ion, initial phenylalanine concentration in aqueous, extraction temperature, and (extraction) pH were mainly investigated. The experiment results indicate that higher phase splitting speed (and extraction) factor can be achieved when low-carbon alcohols such as n-butanol are used as organic solvents; by using five different N-carbobenzyloxy-L-amino acids as chiral ligands that are formated with Cu~(2+) or Ni~(2+), it is found that as a ligand, Z-Phe has a low extraction factor, while Z-Hyp, Z-Pro, Z-Glu, Z-Val have higher extraction factors, and among these, Z-Val has the highest distribution coefficient; pH value of extractant, when near to the PI of phenylalanine, helps to improve extraction resolution effect; temperature has no obvious effect on the resolution result. The result that extraction factor exceed to 1.5 reveals that extraction resolution with N-carbobenzyloxy-valanine is superior to that with N-n-dodecyl-proline.