Heavy metals such as Cadmium (Cd) are one of the most fundamental causes of soil and water pollution in industrialized and developing countries. Cadmium (Cd) is a heavy metal that accumulates in the environment and causes pollution as well as intoxication of both vertebrates and invertebrates, although the mechanisms responsible for the toxicity of Cd are not well understood. Organisms inhabiting chronically polluted environments require additional expenditure of energy for supplementary detoxification. Superoxide dismutase, catalase and glutathione S-transferase (GST), play key roles in protecting organisms from endogenous reactive oxygen species, whose activities are enhanced by environmental contaminants. The wolf spider Pirata subpiraticus (Araneae,Lycosidae) is a common, surface-active wolf spider that inhabits very wet places and can be used as a very important bio-indicator for heavy metals pollution. Here, we used the wolf spider P. subpiraticus as an organism to evaluate the oxidative stress and metallothionein (MT) content. The wolf spider P. subpiraticus inhabiting at four meadow sites along a gradient of heavy metal pollution (the polluted sites: S1, S2 and S3; the control site: S4) were collected and fed with the fruit flies Drosophila melanogaster under free and 20 mg/kg Cd²⁺ medium, respectively. The contents of MT and malondialdehyde (MDA), and the activities of antioxidases of P. subpiraticus were determined. There were no significant differences in Cd accumulation and MT content in P. subpiraticus fed with Cd-free fruit flies. In contrast, Cd accumulation and MT content were significantly less compared with that fed with 20 mg/kg Cd fruit flies. Feeding the fruit flies Drosophila melanogaster with 20 mg/kg Cd²⁺ medium significantly increased Cd accumulation and MT contents of P. subpiraticus from polluted sites, which exhibited the typical time-dependent pattern compared with the control (P<0.05). There were no significant differences in MDA and antioxidant enzymes of P. subpiraticus fed with Cd-free. However, MDA of P. subpiraticus from the polluted sites successively increased and positively correlated with time compared with the control. On the contrary, the activities of GST, SOD, and CAT of P. subpiraticus from the polluted sites successively decreased and negatively correlated with time compared with the control. After 20 days, there were no significant differences in MDA, SOD, and CAT in P. subpiraticus from all sites, except GST. This research indicates that MT production may be an important mechanism enabling P. subpiraticus populations to persist in ecosystems polluted with heavy metals above a certain level and antioxidant enzymes play key roles in protecting organisms from heavy metals polluted.