AC Electroosmosis(ACEO) induced by electric field is the basic approach for non-mechanical microfluid pumping. Traditional ACEO theory is based on electric double layer (EDL) theory, and gives electric-flow field coupling equations for ACEO flo w rate. But there is a big deviation between the calculation data and experimental velocities. In this paper, electrode surface topography is included to solve ACEO flow rate. Withelectrode surfaceroughness as the characteristic parameter, equivalent EDL model is set up to modify the classical EDL model. The relationship between flow rate and electrode surface roughness is studied. Experiment results agree with the simulation very well, proving the feasibility ofequivalent EDL model.