On the basis of the emulsion polymerization process poly(indole-co-thiophene) supported Fe3O4 NPs nanocomposite was synthesized at room temperature. The structure and chemical composition of the nanocomposite were described by scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroScopy. Due to its uniform pore structure, high surface areas and good biocompatibility, the chains of PIT@Fe3O4 nano composite are able to provide a suitable matrix for immobilization of biomolecule. Glassy carbon electrode modified with PIT@Fe3O4 nanocomposite was used as support for immobilization of hemoglobin (Hb) protein to fabricate an electrochemical biosensor. The electrochemical studies for the biosensor shows that it has excellent property for direct bioelectrocatalytic performances of hemoglobin, and could sense hydrogen peroxide at a low detection limit of 0.54 mu M and a linear range up to 350 mu M. The developed biosensor confirmed an excellent performance in the detection of hydrogen peroxide in environmental and food samples. (C) 2016 Elsevier B.V. All rights reserved.