Microencapsulation of sodium ascorbate with cellulose acetate phthalate(CAP) by coacervation/phase separation method were carried out. Various factors affecting microencapsulation, i.e., surfactant concentration, CAP concentration, stirring speed and treatment of spermaceti as a sealing agent were studied. Dissolution rate, particle size distribution, surface feature and stability test were investigated. CAP microcapsules prepared using 0.5% span 80 as a surfactant showed smooth and round surfaces. The release of sodium ascorbate was retarded by microencapsulation with CAP and by sealant treatment with spermaceti. When triturated with sodium bicarbonate, CAP microcapsules were more stable than unencapsulated sodium ascorbate under various RH conditions at 37℃.