It is generally believed that the pesticide used in the corps and veges is harmful for people’s physical health. According to the world health organization up to 200,000 people through out the world are killed by pesticide annually because of the toxic organic phosphorous. What is more the number of people killed by organophosphorous is 100,000. We use the module provided by the organizer of IGEM, base on last year’s result, this year we aim to purify the enzyme in other words avoid the coli from expressing the enzyme. This is especially helpful to make reagent from the purified enzyme, further more, the harmful proteins contained in coli can be eliminated since the opdA is purified, thus narrow the potential danger that the residue may do harm to people’s body.