In order to explore the physiology influence of extract mixture of Ginkgo biloba sarcotesta and Phytolacca americana leaf on the Plutella xylostella and its main victim of cruciferous crop seedlings,the physiological indexes of P. xylostella and radish seedlings which is a typical cruciferous plants before and after mixture treating were determined by direct measurement,microanatomy,spectrophotometry and other methods.Results showed that,the surviving P. xylostella larvae under the treatment of mixture completed the subsequent growth and development process successfully including pupated and cocooned,though the cocoon weight and eclosion rate were significantly lower than those of the control group(P<0.05);The extract mixture did not lead to a obvious intestine changes in shape,colour and apparent structure of the P. xylostella,but reduced the enzyme activities of acetylcholinesterase,carboxylesterase,peroxidase and hydrogen peroxidease significantly which were closely related to the function of nerve conduction,detoxification and antioxidant in P. xylostella(P<0.05);The extract mixture lead to inhibition of height,fresh and dry weight of radish seedlings,and increase of SOD activity,POD activity,MDA content and leaf conductivity,as well as a dynamic change of net photosynthetic rate in leaf.Results suggest that the extract mixture has a synergistic effect on the function of nerve,detoxification,oxidation resistance in the P. xylostella larvae,its toxic effect could last whole life stage of the P. xylostella, and the extract mixture could induce growth inhibitory and physiological responses of the cruciferous crop,so the utilization concentration of mixture should be reduced as much as possible based on effective control to the P. xylostella.