Abstract: Electro-Wetting On Dielectric（EWOD） device introduces the electrodes arrays to define the variational electric field,modify the droplet surface tension,and control the movement of droplet in micro-channel.EWOD is calculated in numerical method.Level set method is used to capture the free surface and solve the surface tension equation.Together with pressure equation and N-S equation,the pressure field and velocity field are calculated.The 3×3 electrodes arrays are utilized to drive the droplet.The result of simulation predicts that the Electro-Wetting make the droplet move on the special track at lower voltage.If the interval of electrodes large than a critical value 100μm,leading the droplet movable from one electrode to next,is calculated in simulation.