【Objective】Phthalate acid esters (PAEs), also known as phthalate esters or "plasticizer", are the reaction product of phthalic anhydride and alcohol. PAEs are widely used in the production of a huge number of products such as agricultural plastic film, toys, medical bags and hoses for transfusion, food packaging, cleansers, vinyl floor and wallpaper, and personal care products. Among them, Di(2-ethylhexyl) phthalate (DEHP) is one PAE, the highest in output and consumption and also a toxic organic compound highly hazardous to human health, disturbing endocrine systems and causing cancers, mutation, oxidative damage and genetic toxicity. As DEHP is weakly bonded to the plastic matrix by hydrogen bond and van der Waals force, it is easily detached and diffused into the air, water and soil environments. Therefore, its pollution and hazard to human health has aroused more and more attention from the people. So far studies have proven that DEHP can enter organisms via a variety of ways, causing poisonous damage to tissues and organs of the organisms. As DEHP is extensively used in agriculture and hence exists in large volumes in the soil system, it is necessary to investigate its ecological and toxicological effects, such as oxidative stress and DNA damage, on typical soil animals, in the hope that the study may serve as scientific basis for reasonable assessment of soil ecological risk of DEHP.【Method】To explore eco-toxicological effects of DEHP on soil animals, Earthworms (Eisenia foetida), used as bio-indicator, were exposed to DEHP varying in concentration (0, 0.1, 1, 10 and 50 mg kg^-1) in artificial soil. Earthworms were sampled after 7, 14, 21 and 28 days of exposure for analysis of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and glutathione (GST), which are the indices reflecting the degree of DEHP activating oxidation of earthworms, reactive oxygen species (ROS), which is the indicator of cytotoxicity of DEHP to earthworms, and malondiadehyde (MDA) and olive tail moment, which are the indices reflecting genotoxicity of the substance to earthworms.【Result】 (1) DEHP, above 0.1 mg kg^-1 in concentration, significantly enhanced the activities of SOD, CAT, POD and GST in Eisenia foetida by a degree varying with the concentration of DEHP, which demonstrates that DEHP induces antioxidant enzymes in earthworms; (2) DEHP increased ROS concentration in earthworms as compared with control and the effect varied between treatments, displaying an apparent dose-effect relationship;(3) Comparison between the treatments shows that DEHP did have some effect on content of MDA, but the effect did not follow any specific rule and was the most obvious in earthworms exposed to DEHP, 10 mg kg^-1 and 50 mg kg^-1 in concentration; (4) In the presence of DEHP. GST in the earthworms was apparently activated, except for the treatment of 0.1 mg kg^-1, where the earthworms did not have much difference from those in control. The observation demonstrates that DEHP, higher than 0.1 mg kg^-1 in concentration induces GST in the earthworms; (5) Single cell gel electrophoresis shows that coelomocyte DNA of the earthworms was damaged in the presence of DEHP, regardless of concentration and Olive tail moment increased with the rising DEHP concentration, which suggests that DNA damage caused by DEHP is dose-dependent.【Conclusion】 Once DEHP enters earthworms, it activates the defense system of antioxidant enzymes (SOD, CAT and POD) and GST detoxification enzyme in the earthworms to protect the organisms from injury. Nevertheless, DEHP still raises ROS content in the earthworms, and excessive ROS triggers peroxidation of lipids, producing MDA. ROS and MDA act jointly damaging cell DNA of the earthworms. To sum up, DEHP may cause a certain degree of damage to organisms and DNA of the earthworms, manifesting fairly strong eco-toxicological effects. Therefore, adequate attention should be paid to DEHP disposal.