Abstract: Through co- precipitation and sol- gel method,the Fe3O4- Si O2 nanoparticles was prepared. The surface of Fe3O4- Si O2 magnetic nanoparticles was modified with amino.Finally,the magnetic nano- composite carrier was obtained.The surface features of the carrier by Scanning electron microscope and Fourier Transform Infrared Spectrometer was described. Through the investigation of the effect of amount of enzyme,concentration of glutaraldehyde,immobilization time and temperature on protein solid load rate and lipase activity,the optimum conditions of lipase immobilization was obtained. Under the condition of the amount of lipase solution( 0.02 g / m L)was 8.30 m L,the concentration of glutaraldehyde was 8.20%,the temperature was 24℃ and the immobilization time was 4h,the obtained immobilized lipase enzyme activity was 3449 U / g.