Microbubble-agitated extraction was conducted with microextractors for process intensification of extraction with high phase ratio. Hexanoic-acid/water/n-octanol system with phase ratio of 80 was selected as a model system. Single and double membrane dispersion modules were developed for generating liquid-liquid and gas-liquid-liquid microdispersion systems. 10 different methods, 6 of which containing microbubbles, were designed to realize high-phase-ratio extraction. The effect of dispersion size, structure of gas-liquid-liquid emulsion and amount of microbubbles were systematically investigated. The most efficient and stable mode was recommended, with which Murphree efficiency could reach 90% in 0.5 s and the overall volumetric mass transfer coefficient ranges in 7.88-41.34 s(-1), about 40 times greater than liquid-liquid system. The mechanism of the intensification effect by introducing microbubbles was discussed. Two typical gas-liquid-liquid structures were selected to study the effects of microbubbles in adjusting phase ratio and promoting turbulence in continuous phase. Two dimensionless equations were established to correlate mass tranfer coefficients respectively, both of which showed good coincidence with experimental data. (C) 2017 Elsevier Ltd. All rights reserved.