The efficiency of removal of pesticide residues on vegetables was evaluated by the toxicity bioassay. The results showed that treatment with H2O2 at concentration of 10 mL/L for 1 day, the residue of methami-dophos and chlorpyrifos decreased 10.57% and 16.95%, and the degradation rates were 39.62% and 30.49% at 3 days after treatment, and 7 days later, the degradation rates were 45.21% and 64.05% . The toxicity bioassay of the pesticides on the surface of plant leaf against 3rd-instar larvae of Spodoptera litura showed that treatment with H2O2 for 60 min was able to decrease the toxicity of methamidophos, chlorpyrifos, monocrotophos to a certain extent.