Abstract:as carbon sources,FeCl3as the cross-linking agent and magnetization agent. Synchronous molding andmagnetization were realized by the cross-linking reaction between sodium alginate and FeCl3. The MBwas characterized by analysis methods such as BET,SEM,XRD,FT-IR and VSM. The results provedthat MB had large specific surface area and good pore structure. MB showed good magnetism because itssurface was successfully loaded with Fe3O4. The surface of MB prepared by low-temperature pyrolysiswas rich in oxygen functional groups,so it was easy to complex with Pb (Ⅱ). When initial pH=6,MBaddition=10% and adsorption time = 24 h,the optimal removal rate and adsorption capacity of MBprepared by 300 ℃ pyrolysis were 67.53% and 3.11 mg/g,respectively. The adsorption process fittedthe quasi second order kinetics equation,and was mainly chemical adsorption. After adsorbing Pb (Ⅱ)in soil,MB could be separated and recovered by external magnetic field,and the recovery rate was morethan 95%. After 5 times of regeneration,MB could still maintain 71% of the initial adsorption of Pb (Ⅱ). Close-