A promising method for removing heavy metals from contaminated soil is phytoremediation. Heavy metal cations are strongly adsorbed onto the negatively charged soil part icles, which limits the development of phytoremediation. To enhance metal solubility and bioavailability, some natural or synthetic chelators (e. g. organic acids and EDTA) and inorganic acids have been used. In this study organic chelators such as Citric acid, Oxalic acid, Tartaric acid, Malic acid and their salts, EDTA and Nitric acid solutions for soil metal activation were used. The results showed that the trends of Cu, Zn and Pb released by the organic acids were: Citric acid> Oxalic acid> Tartaric acid> Malic acid for Cu, Citric acid> Malic acid> Oxalic acid > Tartaric acid for Zn and Citric acid> Tartaric acid> Malic acid> Oxalic acid for Pb. The organic sodium salts including Citrate, Tartarate and Oxalate had lower release capacity, but synthet ic chelator EDTA had higher release capacity, and the releasing trends of Cu and Zn by the organic salts were EDTA> Citrate> Oxalate> Tartarate, but for Pb, the order was EDTA> Citrate> Tartarate> Oxalate. 1.0 mol L^-1 and 0.1 mol L^-1 HNO₃ had the highest release capacity, which had significant difference from that of 0.01 mol L^-1 HNO₃. Considering their application to enhancement phytoremediation, EDTA and Citric acid with higher release capacity would have more promising potential in term of protection of soil quality.