First, the phase diagrams for the water+ethanol+fatty acids system were described, and the separation method was considered. Second, the separation of lauric acid+myristic acid mixture in the ethanol aqueous solution including ethanol by liquid-liquid extraction and crystallization has been examined. The extraction of fatty acids from the organic phase to the aqueous solution has been done. Fatty acids in the aqueous solution were crystallized using the aqueous SLE surface. The solvent-free mole fraction of lauric acid in the aqueous solution was a little higher than that in the organic phase. Fine crystals made in the aqueous solution had better purity for lauric acid than the solvent-free mole fraction of lauric acid in the aqueous solution. The effects of the mole fraction of ethanol in the aqueous solution, the mole fraction of lauric acid in the organic solution, extraction temperature and crystallization temperature on the purity of the crystals were reported.