Abstract: By studying Pb polluted rice straw matrix during fermentation,the degrading function of hemicellulose,cellulose and lignin and the changing regularity of fermentation substrate and humus carbon were discussed during fermentation under the different Pb²⁺ concentration.Then Pb passivated action of heavy metal ions in fermentation substrate was also researched during degradation of hemicellulose,cellulose and lignin.The result showed that,under 200(mg/kg) Pb²⁺ concentration,white-rot fungi had a strong capability in degrading organic such as hemicellulose,cellulose and lignin in rice straw,and had obvious passivation action for Pb²⁺;the degradation rate of hemicellulose,cellulose and lignin reached(52.36%,)(32.29%) and (44.16%,) respectively;the weight loss rate of matrix weight and contents of humus carbon reached(29.89%) and(142.01)(mg/g) respectively.