Abstract: The technological process for producing biodiesel from rapeseed oil transesterificated by ethanol with lipase LVK as a catalyzer in hexane was optimized. In order to improve the rate of transesterification, the response surface methodology was used to optimize the reaction process. Optimum conditions for the production of ethyl esters were as follows: the molar ratio of ethanol to rapeseed oil is 5.3∶1, concentration of catalyst 15.0%, solvent(hexane) concentration 18.4%, reaction temperature 40℃ and reaction time is 34.5 h, respectively. Under these optimized conditions, the transesterification ratio reached 93.48% when ethanol was added only once. The result shows that this solvent system with hexane cannot only improve the solubility between ethanol and rapeseed oil, but also eliminate the denaturalization effect of ethanol to lipase.