In this paper,methyl 2-(6-methoxy2-naphthyl) propionate (naproxen) was asymmetrically hydrolyzed by candida rugosa lipase in pseudo-eutectic and organic solvent systems.The result showed that S-(+)-naproxen with enantiomeric excess more than 95% could be obtained with commercially available candida rugosa lipase in both systems.In organic solvent system, 24.1% reaction conversion of naproxen methylester could be obtained after 96 hours, while in pseudo-eutectic systems,the conversion was 4011% after 72h. Furthermore,only one fifth organic solvent volume was used in pseudo-eutectic systems.Compared to organic solvent systems,the effects of lipase concentration,substrate and water concentration,and several different kinds of adjuncts on reaction conversion were studied in pseudo-eutectic system1 Also,under the optimium pseudo-eutectic enzymatic reaction conditions,the reaction conversion was 45.8%.