Abstract: In order to study on the remediation mechanism of bentonite on copper contaminated soil, a pot experiment of rape was conducted to study the effects of clay minerals about bentonite on soil enzyme activity of copper contaminated soil. The results showed that: activities of urease, alkaline phosphatase, catalase and nitrate reductase in soil were significantly restrained with increase of concentration of copper in contaminated soil. Bentonite significantly increased activities of urease, alkaline phosphatase, catalase and nitrate reductase by 6.4%-15.4%, 4.0%-19.3%, 1.26%-1.85%, 4.6%-10.9% in the copper contaminated soil, respectively and the increase rates of 4r enzyme activity were in order: alkaline phosphatase＞urease＞nitrate reductase＞catalase. Increase rates of urease and alkaline phosphatase activities were greater in high concentration copper contaminated soils than in the low concentration of copper contaminated soils, but catalase and nitrate reductase activities were greater in low concentration than in high concentration of copper contaminated soils. Therefore, bentonite could amend copper contaminated soils.