Abstract: The condition for enzyme immobilization was studied by using polypropene loaded titanium dioxide membrane to immobilize pesticide degradable enzyme EC3.1.2.8. Methyl parathion was selected to carry out the degradation experiment. The result showed that the optimal time, temperature and concentration for enzyme immobilization were 1.5 hours, 20℃ and 160 mg/(100 mL), respectively. The optimal temperature for immobilized enzyme to function was increased by 5℃ compared to free enzyme. The optimal pH value for it to degrade methyl parathion was 8.5. The degradation ratio of immobilized enzyme to methyl parathion in 30 minutes was more than 70% and the immobilized titanium dioxide membrane had good stability.