The transesterification of fatty acid in maize germ oil deodorizer distillate with methanol catalyzed by immobilized lipase Novozym 435 and tert-butyl alcohol as solvent in the reaction system was studied. The optimal condition was fixed by single factor test. The results showed that the addition of lipase was 80 mg/g, reaction temperature 55℃, reaction time 20 h, the molar ratio of substances 1.5:1, the addition of tert-butyl alcohol 6%, then the esterification rate reached 96.84%. The lipase was treated with acetone after each reaction can be recycled 7 times without significant loss of activity.