The principle，the key influential factor of enzyme inhibition spectrophotometry for determination of organophosphate and carbamate pesticide residues in vegetable had been described,and had discussed the insufficient problems such as false positive results, negative enzyme inhibition rate which exists in this enzyme inhibition spectrophotometry and why organophosphate and carbamate pesticide residues in certain vegetables such as leek cannot be determined with this enzyme inhibition spectrophotometry．