Kerosene-in-water emulsions were de-emulsified by narrow plate-type microchannels. The emulsions with different Sauter diameters of 5 or 10 mu m were formed by high-shear homogenization method and passed through microchannels with clearances of 100 to 200 mu m. The de-emulsification efficiency was from 10% to 30% in a single pass through the channel. By repeatedly passing through the microchannels, up to 90% de-emulsification efficiency can be achieved. The results showed that the de-emulsification efficiency was influenced by the flow rate, Sauter diameter, microchannel size, and wall materials. Hydrophobic surface of the microchannel improved the de-emulsification efficiency. A coupled two-step mechanism was proposed to illustrate the de-emulsification process. Specially, polytetrafluoroethylene-stainless steel (PTFE-SS) plate combination of the microchannel induced different velocities of the continuous phase close to the wall surface and helped the droplets of the emulsion move toward the PTFE wall and be captured.