Based on the synergic effect of multi-walled carbon nanotubes(CNTs) and thionine(Th)，a novel hydrogen peroxide electrode(HRP/GA-Th/CNTs/GC) was fabricated by immobilizing horseradish peroxidase(HRP) onto the thionine(Th) /multi-walled carbon nanotubes modified electrode via glutaradehyde(GA) cross-linking.The introduction of CNTs into the electrode is helpful for the further immobilization of Th and the catalysis to H2O2.Furthermore，Th immobilized on CNTs by electrostatic adsorption not only can transfer electrons between the electrode and the redox activity center of the enzyme，but also can enable amine group(—NH2) in Th to provide convenience for the immobilization of HRP enzyme via glutaradehyde cross-linking.Additionally，effects of various experimental parameters on H2O2 sensing，including applied potential，pH value and electroactive interferent，were investigated.At an optimal potential of -0.3 V，the current response of the biosensor in phosphate buffer(pH 7.0) was linear with H2O2 concentration from 5 μmol?L-1 to 40 μmol?L-1，with a good detection limit(0.3 μmol?L-1)，a short response time(within 5 s) and a good anti-interferent ability.