The rapid decomposition of hydrogen peroxide (H2O2) is often desired in the cleanup of excess H2O2 when it is used as an oxidant. Although the decomposition process has been studied in batch reactors, it has never been performed before in a fixed-bed microreactor with residence time on the scale of seconds. With enhanced mass and heat transfer in microreactors, higher H2O2 decomposition efficiency compared to batch reactors was obtained. A variety of parameters including length of microchannels, flow rate, solvent composition, and gas pressure were examined carefully and a first-order kinetic model was established. Within a few seconds, more than 70 % of the H2O2 was decomposed successfully. The challenge of catalyst passivation was discussed as well.