Multi-walled nanotubes（MWNTs） is self-assembled onto the coated glassy carbon elecrtode（GCE） to form a negative-charge surface.Cationic dye-thionine（Thi） is linked by electrostatic adsorption as an electron transfer mediator.Next the mixture of gold nanoparticles（GNPs） and chitosan（CHIT） is assembled on the electrode by covalent bond.The positively charged horseradish peroxidase is successfully immobilized on the GNPs surface.The electrocataltyic behavior of the modified electrode to H2O2 is investigated by cyclic voltammetry and chronoamperometry.The experiments show that the modified electrode has excellent electrocatalytic activity for the detection of H2O2.The linear range of this biosensor is 8.2×10-6

1

.1×10-3 mol/L with a detection limit of 5.8×10-7 mol/L.The response time achieved 95 % steady state is about 15 s.The biosensor is applied for deteetion of H2O2

and the results are satisfied.