This study uses nano-scale zero-valent iron with hydrogen peroxide to treat pentachlorophenol contaminates soil with the expectation to offer new and effective solution for future treatment work. The primary study indicates that the BET specific surface area of nano-scale zero-valent iron is about 34.9 m(2)/g. When different content percentages of nano-scale zero-valent iron with 0, 0.2, 0.5, and 1 wt.% are added to 1 % H2O2 for oxidation, 1 wt.% is found to give the best result to treat pentachlorophenol-contaminated soils. Among three types of sampling soils, Pianchen (Pc) series is proven to be more effective because zero-valent iron releases Fe2+ during oxidation. Addition of H2O2 promotes the generation of Fenton with OH center dot and oxidation-reduction reaction. Due to the dual mechanism, the phenol compounds that are otherwise difficult to be removed are now effectively treated. This study also indicates that when 5 % of calcium carbonate is added for 40 h, the decay rate on pentachlorophenol of Chengchun (Cf) series soil is from 37% to 78%, and Pianchen (Pc) series is from 43% to 76%. The result of treatment of pentachlorophenol-contaminated soil using the added calcium carbonate is a new treatment method and serves as the reference for future on-site treatment. (c) 2006 Elsevier B.V All rights reserved.