In this work, the mass transfer characteristics of two immiscible fluids were investigated in a rotating helical microchannel with hydraulic diameter of 932μm. Aqueous phosphoric acid solution and 80％tri-n-butyl phos-phate (TBP) in kerosene were selected for the investigation of mass transfer performance in quartz glass/high density polyethylene (HDPE) microchannel. High dispersion between the two immiscible fluids can be obtained in the microchannel due to the intensifying action of centrifugal force, and the majority of the droplets with av-erage diameter of 20–100μm were produced in the microchannel. The flow rate and rotation speed were found to have great effects on the extraction efficiency and average residence time. The empirical correlation of average residence time based on experimental data was developed by theoretical analysis and data fitting method, and a mathematical model of the mass transfer coefficient in dispersed phase was proposed.