Recently, graphene based magnetic nanocomposites have been widely used in several fields, such as targeted drug carrierl, pollution control2.In current proteomics research, protein digestion is important to follow-up study.High amount of enzyme immobilization and low protein residue is the goal of enzyme reactor.Graphene oxide (GO) has large surface area and considerable hydrophilic groups, which make it meet the requirements of the enzyme reactor.Furthermore, the introduction of magnetic nanoparticles can significantly simplify operation procedure and can absorb microwave to improve enzyme efficiency.