Lipoxygenase which is a kind of peroxidase could be used in many facets of industry. The stability and using times of the enzyme would be increased after the enzyme was immobilized by appropriate methods and materials. In this study, nanometer Fe₃O₄ was prepared by hydrothermal method and modified with SiO₂ and KH550 to obtained composite carriers. Lipoxygenase was immobilized on the composite carriers by glutaraldehyde. The influence factors on enzyme activity for free and immobilized enzyme were studied. The TEM results showed that the black nanoparticles were rod shaped. The mass of enzyme immobilized on the composite carriers was about 14% of the immobilized enzyme mass. The activity of free enzyme was 1.82×10³ U/mL while its optimum temperature and pH were 30 ℃ and 80, respectively. The activity of immobilized enzyme was 2.31×10³ U/g while its optimum temperature and pH were 25 ℃ and 9.0 respectively. The free and immobilized enzyme exhibited the highest enzyme activity when H₂O₂ concentration was 12.0 g/L. The results indicated that it was a feasible method to immobilize lipoxygenase by nanometer Fe₃O₄, and it was deserved to be further studied.