Abstract: The aim was to research principle and effect of decreasing the toxicity of Pb in the Pb-contaminated soil. Three organic fertilizers were added in the pb-contaminated soil. The forms of Pb were analyzed. The results suggested that there were very significant effect on the exchangeable speciation; carbonate bound and organic matter bound. The Fe-Mn oxide of Pb had no significant effect and the residual form had significant effect by cattle manure treatment. All the forms had very significant effect by the chicken manure and pig manure. The right amount of organic fertilizers can reduce the exchangeable speciation, carbonate and bioavailability, respectively and increased the Fe-Mn oxide, organic matter bound and residual form. The effects of the three organic fertilizer treatments were chicken manure＞cattle manure＞pig manure. The organic fertilizer changed the forms of Pb and reduced the bioavailability. The organic fertilizer is a better amendment of controlling heavy metal contaminated soil.