The optimization of determination for organophosphate pesticide residues in vegetables was studied. In the promise of higher sensitivity, a new low cost reagent components, whose dosage of acetylcholinesterase (AChE), substrate and chromogenic reagent were 3/4, 3/4 and 1/2 that of original components respectively, thus saved cost of reagent. The result was achieved through contrastive test. F-test proved that there was no significant difference between adjusted components and original components. The lower limit of determination of adjusted components to three pesticides is omethoate 0.37 mg/L, trichlorphon 0.09 mg/L, dichlorvos 0.035 mg/L, which is consistent with those of national standard rapid determination method.