The extraction of L-Arginine with di(2-ethylhexyl)phosphoric acid(D2EHPA) has been studied as functions of equilibrium pH, D2EHPA concentration, L-Arginine equilibrium concentration, NH 4Cl concentration and temperature. The beffer extraction results were obtained in condition of pH=5～7, D2EHPA 0.2～0.4 mol/L, NH 4Cl<0.2 mol/L and low temperature. The equilibrium concentration of L-Arg depends on the saturation extraction capacity.
