A novel hydrogen peroxide (H2O2) sensor was fabricated by electrodepositing Ag nanoparticles (NPs) on a glassy carbon electrode (GCE) modified with ionic liquid functionalized multiwalled carbon nanotube (MWCNTs-IL) composites. The AgNPs/MWCNTs-IL composite was characterized by different methods including scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The constructed electrode exhibited good catalytic activity toward the reduction of H2O2, and obtained a linear response to logarithm of the H2O2 concentrations ranging from 1.2 x 10(-8) to 4.8 x 10(-6) M with a limit of detection (LOD) of 3.9 x 10(-9) M. Moreover, it can be applied to real samples analysis. The excellent performance of hydrogen peroxide sensor were ascribed to the MWCNTs-IL composites being used as effective load matrix for the deposition of AgNPs and the synergistic amplification effect of the two kinds of nanomaterials - AgNPs and MWCNTs. Therefore, the catalytic mechanism of the constructed sensor was proposed. AgNPs dispersed on MWCNTs-IL were used as the catalyst for the H2O2 into O-2, and the generated oxygen transported the electrode surrounding where it was detected by reduction on the electrode. (C) 2013 Elsevier Ltd. All rights reserved.