The key technology in enzymatic extraction of oil in the aqueous system is the enzymatic hydrolysis and demulsification performance. The process of extracting rice bran oil by enzymatic method under aqueous system is studied in this research. The results show that more than 84.10% rice bran oil extraction yield could be obtained under the following procedure and conditions. The extruded rice bran is screened through a 40- mesh sieve and mixed with ultrapure water at a ratio of 1∶7.5 (w/v), after which 2% (w/w) Alcalase 2.4 L is added to the mixture and the system is continuously incubated for 150 minutes at 57 ℃ and pH 9.0. After centrifugation, the pH of the emulsion to 7.0 reacting is adjusted further at 60 ℃ for 60 minutes to obtain the oil by breaking the emulsion. The quality of rice bran oil extracted, especially the content of bioactive substances, is obviously better than that extracted by the traditional solvent method. In addition, carbohydrase could not improve the oil extraction yield, while alkaline conditions are more favorable for rice bran oil extraction. Alkaline conditions and CaCl2 treatment are not conducive to demulsification, while 20%~30% ethanol treatment could improve the demulsification rate of the emulsion. The technology can promote the applications of aqueous enzymatic method in the vegetable oil manufacture industry, as well as the utilization of rice bran.