In this paper， it reported an acetylcholinesterase(AChE) and choline oxidase (COD) were immobilized and co-modified on the bare gold electrode surface by electrodeposition to construct a novel immobilized enzyme biosensor. The morphology of immobilized enzyme was characterized by electron microscope. The results showed that the comodification layers of immobilized acetylcholinesterase and immobilized acetylcholinesterase in immobilized enzyme biosensor were 2 layers and the number of modification cycles was 35. When the concentration of acetylcholine chloride substrate is 2 mmol/L and pH value is 7.8， the biosensor can recognize the organic phosphorus pesticide signal and has a good detection performance， with a good sensor current response at the organic phosphorus pesticide concentration of 10-9 to 10-7 mg/L. The working curve equation is y=0.0468x + 1.2124 (R2=0.9985)， and the lowest detection limit is 1.15×10-11 mg/L (S/N=3). This research method will provide a new research direction for the rapid detection of organophosphorus pesticides in the field.