Magnetic nano-Fe3O4 was prepared by hydrothermal method which was further to synthesis S2O2-8/Fe3O4, a magnetic nano-catalyst prepared by impregnation and ultrasonic method. Benzyl butyrate was catalytic synthesized with S2O2-8/Fe3O4, the influences of the loaded amount over the catalyst, activation temperature on the reaction were researched, and the recovery and reuse of the catalyst were discussed. The results indicate the esterification rate of the synthesized reaction by impregnation method is 85.6%, the purity of the product is 94.1%, while the selectivity of the catalyst obtained by ultrasonic method have an advantage over it obtained by impregnation method. 