In power electronic liquid cooling systems, the hydraulic circuit is generally implemented by a mechanical pump, which is big, noisy, expensive, and has a high power consumption. To solve these problems, it is proposed to replace the mechanical pump by an electrokinetic one, such as an electroosmotic (EO) pump. In this paper, we present the theory of electroosmosis phenomena and the model and design of a porous EO pump (PEOP). The PEOP is fabricated on the base of two types of porous ceramics (sintered alumina and silica). Using deionized water as pumping liquid and silica, the PEOP generates 13.6 mL/min and 2 kPa at 150-V applied voltage. The power consumed by the pump is less than 0.4 W. The PEOP works without any bubbles in the hydraulic circuit. This pump can be used to cool 22.6 W of power generated by the power components with a forced convection without evaporation and 270 W with evaporation. A test experiment with alumina shows a good accordance in terms of pressure and flow rate with the PEOP model.