The theoretical modeling of EHD pumping is a complex process governed by the electrostatic and hydrodynamic partial differential equations. The exact solution of these equations is quite difficult therefore, the numerical methods are used to investigate and simulate the EHD pumping. In most of the cases the numerical solution is obtained by the available simulation packages based on the finite element methods that limit the analysis with built in functions. In this paper for the first time EHD ion-drag pumping at the micro scale is simulated by using finite difference method. A user defined code is written in MATLAB and the interactive simulation patterns for electric potential, electric field, velocity field and pressure field are obtained and also compared with finite element method. It was found that the finite difference simulation is significantly in agreement that of by finite element method. The former provides more control and ease to analyze and predict the performance of ion-drag micro pumps.