A gas-liquid-liquid microdispersion system was specially designed to realize a microbubble-agitated extraction process for the intensification of extraction with high phase ratio. The process with the phase ratio larger than 50 for H2O2 extraction was taken as a typical case. A microstructured system with 5 mu m pore size microfiltration membranes as the dispersion medium was developed to generate the gas-liquid-liquid microdispersion system. Considering three different microdispersion modes, the most efficient mode was suggested with lower addition of gas, by which the Murphree efficiency could reach higher than 90% and the overall volume mass transfer coefficient could range in 0.2-21.9 s(-1), 10-30 times greater than the extraction process without gas addition. A unified mathematical model in the form of K(o)a = 0.8we(0.6)Phi(0.6) (p was developed to predict the mass transfer in liquid-liquid microdispersion extraction process with/without gas addition. (C) 2011 Elsevier B.V. All rights reserved.