A low-cost magnetic composite (gelatin/Fe3O4) is prepared by Fe3O4 nanoparticles treated with gelatin using an environmentally-friendly plasma technique, and is applied for the removal of toxic Pb(II) ions from aqueous solutions. Not only that it originates from cheap and abundant raw materials, the gelatin/Fe3O4 composite also has advantages in convenient magnetic separation from aqueous solution, which can hopefully reduce water treatment expenses. The batch experimenta results indicate that the maximum adsorption capacity (q(max)) of Pb(II) on this gelatin/Fe3O4 composite is approximate to 115mg/g, higher than most of the other bare and modified magnetic materials, which is considered to be attributed to the strong interaction between Pb(II) and the abundant functional groups introduced by gelatin. When exposed to acidic solutions, the dissolution of the gelatin/Fe3O4 nanoparticles is minimal due to the protective character of the grafted gelatin layer on the Fe3O4 nanoparticles. The utilization of the plasma technique in the synthesis of magnetic composite agrees well with the tenet of green chemistry. It is promising that this gelatin/Fe3O4 composite would become an efficient and economic material for heavy metal ion removal in the practical environmental remediation.