Abstract: The butyrylcholinesterase of donkey serum as enzyme source, testing conditions and methods of different organophosphorus pesticide were studied. Pesticide residues in vegetables were determined by the method of enzyme inhibition in Jinzhou at the same time. The results showed that IC 50 of rogor, trichlorfon, dichlorvos and malathion were 0.094, 0.179, 0.124, 0.0078mg /mL separately. The donkey serum butyrylcholinesterase of the four kinds of organophosphorus pesticide were sensitivity of the size to the order:malathion > rogor > dichlorvos > trichlorfon.The best time of inhibiting the butyrylcholinesterase for the rogor and dichlorvos were 15min but others were 20min.Vegetable samples of three farmers market were determined by enzyme inhibition method.The results found that two cases in chives, one case in rape and two cases in green peppers were exceeded on organophosphorus pesticide residues.Passing rate of samples reached 86.1%.