In this article, to miniaturize the hydrogenation reactor and make the H2O2 production with more safety a gas-liquid microdispersion system was generated to intensify the process of catalytic hydrogenation of ethylanthraquinone by passing the gas-liquid microdispersion system through a generally packed bed reactor. A microdispersion device with a 5 mu m pore size microfiltration membrane as the dispersion medium has been developed and microbubbles in the size of 10100 mu m were successfully generated. The reaction and mass transfer performance was evaluated. The conversion of ethylanthraquinone as much as 35% was realized in less than 3.5 s. The overall volume mass transfer coefficient in the microdispersion reaction system reached in the range of 121 s-1, more than two orders of magnitude larger than the values in normal gas-liquid trickle-bed reactors. A mathematical model in the form of Sh = 2.0 + 54.7Sc1/3We1/2?1/10 has been firstly suggested, which can well predict the overall mass transfer coefficient. (c) 2011 American Institute of Chemical Engineers AIChE J, 2012