In this research, results of an experimental study of prickly ash seed cust oil on the preparation of fatty acid methyl ester by lipase catalysis were presented. Factors such as n-hexane, the FAME rate, water concentration, volume of lipase, et al were studied. The experiment results showed that n-hexane is most suitable solvent in the non-aqueous lipase catalytic system and the FAME rate reach the optimum when n-hexane concentration is 15%(w/w), water play an important role in the system and 10% is optimal concentration, When amount of lipase was 25%(w/w), n-hexane concentration was 15%(w/w), water content was 10% (w/w), methanol: oil was 3:1, the conversion rate was as high as 82.5% with pre refined oil and the conversation rate reach 93.5% after refine the oil at optimum experimental condition.