Abstract: Objective: Trypsin was immobilized on the Si O₂ by biomimetic silicification process.The catalytic films were prepared by suspending the immobilized trypsin directly into a poly ( methyl methacrylate) solution in toluene.Methods: The concentration ratio of TMOS and enzyme, mass ratio of MPS and enzyme and the type of organic solvents were studied. Compared with mesoporous silica ( MPS) immobilized enzyme, the storage stability of the composite films, catalytic activity, reusability, and resistant to protein adsorption properties was studied.Results: The results indicated that the Si O₂-Enzyme-PMMA film showed the better stability.After 30 days, the residual activity of Si O₂-Enzyme-PMMA film and MPS-Enzyme-PMMA film were86.3% and 81.2% of the initial activity, respectively.The Si O₂-Enzyme-PMMA film also showed good operational stabilities in six times of continuous operations.The enzyme residual activity was 89.1%.The surface protein adsorption capacity of Si O₂-Enzyme-PMMA film immersed in BSA solution for 18 days was only 1/3 of the PMMA film without enzyme.The two films both had good adsorption properties resistant to protein. Conclusion: Compared with the mesoporous silica carrier, Si O₂ prepared by biomimetic silicification process had higher stability and embedding rate. The method had the advantages of mild condition, simple operation and high activity, and can be used in the anti fouling coating.