Aiming to enhance the adsorption capacity of heavy metal onto lignocellulosic biomass and reveal the adsorption mechanism involved, wheat straw samples pretreated by hydrothermal, sulfuric acid, phosphoric acidhydrogen peroxide, microwave, alkali and alkalihydrogen peroxide, respectively were prepared. The changes in the microstructure, chemical components, and Pb2+ adsorption capacity were analyzed. The results revealed that the physicochemical pretreatments of wheat straw, such as hydrothermal, sulfuric acid, phosphoric acidhydrogen peroxide, microwave, alkali and alkalihydrogen peroxide, had different adsorption effects on Pb2+, and the adsorption capacity of Pb2+ was 1.01mg/g, 1.51mg/g, 3.99mg/g, 6.57mg/g, 9.56mg/g and 9.76mg/g, respectively. The hemicellulose can be removed effectively by the acidic conditions, lignin can be removed mainly by the alkaline conditions, and the degradation of lignin was further enhanced by the hydrogen peroxide, while microwave treatment was relatively weak. The quantitative analysis showed that the Pb2+ adsorption capacity was mainly positively correlated with content of hemicellulose, which can be described by the following equation Y=0.44X-0.09 (R2=0.83), and negatively correlated with content of lignin as the following linear relationships Y=-0.33X+12.95 (R2=0.81). Moreover, the importance of components to Pb2+ adsorption capacity in descending order was acidinsoluble lignin (AIL), hemicellulose, lignin, other components, cellulose and acidsoluble lignin (ASL). Thus, the content of hemicellulose was a key factor affecting the Pb2+ adsorption capacity of wheat straw. Therefore, the research result would help to establish the foundation for elucidating the quantitative correlations between lignocellulosic components and adsorption capacity and adsorption mechanism.