Abstract:The tolerant mechanism of earthworm to copper was studied in a mixed medium of soil and organic material with a volume ratio of 1∶1. The medium was contaiminated with CuSO4?7H2O and five levels of Cu2+ (0, 20, 60, 100,200) mg?kg-1 were designed. Each treatment was replicated three times and 10 earthworms (Eisenia fetida) were added for each replicate. The effect of Cu on the weight of earthworm and its copper accumulation characteristicss in epidermis and the gut was studied. Result showed that: the weight of earthworm had a parabola changing tendency with the increase of soil copper concentration. The growth of earthworm was enhanced by copper at low copper concentration and was restrained when Cu2+ concentration＞60mg/kg. If Cu2+＞100 mg/kg, with the lengthening of the exposure period and the increasing of copper concentration, the restraining effect was more significant or even causing decline in body weight.Both of Cu content and Cu total accumulation in epidermis and gut were increased with the increasing of copper concentration and culturing time. The accumulating rate in gut was higher than that in epidermis. The increase of Cu concentration in medium could stimulate the transportation Cu from gut to epidermis sebum system. The ratio of Cu concentration in epidermis to that in gut was declined with the increase in copper dosage, but was risen by time. Earthworm had strong copper accumulation ability.The gut was 2.65 times the content of the environment when exposed in a medium with copper concentration of 200 mg/kg for 21 days,and the total accumulation reached to 0.674 mg per 10bar. The result should has an important significance in the research of the tolerant mechanism and the remediation ability of earthworm for polluted soil.