Abstract: In order to reveal the toxicity effect and risk of co-exposure of Cu and chlorpyrifos in the current soil environment of China, using the earthworm Eisenia fetida as model organism, the effect of single, and co-exposure of Cu and chlorpyrifos on the growth and antioxidant response of earthworm were analyzed by using the methods of filter paper test and artificial soil test. The results showed that the growth rate of earthworm tended to decrease with the increase of single exposure concentrations of Cu and chlorpyrifos in artificial soil test. The mass of earthworm had a relatively flat changing rate with the co-exposure of Cu and chlorpyrifos. Using the addition of probability, the q values of different concentration groups of Cu and chlorpyrifos on the earthworm mass were less than 0.55, which indicated significant antagonistic effect. The joint effect of Cu and chlorpyrifos on the activities of CAT and SOD indicated antagonistic effect in filter paper test, while the effects of co-exposure of Cu and chlorpyrifos on the contents of GSH and MDA showed a synergy effect of low concentrations and antagonism effect of high concentrations.