A method is proposed for simulating the electrohydrodynamics (EHD). The level-set method is used to capture the interface to take its advantage in handling topological change. In order to accurately solve the Poisson equation with interface jump conditions for the electric potential, a simple version of the level-set based immersed interface method (IIM) is developed. This version avoids the local coordinate transform in the original IIM in literature, reducing the complexity of the algorithm significantly. The IIM achieves second-order accuracy for both the electric potential and its gradient. A level-set extrapolation procedure is presented to calculate the electric surface force. Numerical simulations on drop deformation, breakup and coalescence in both 2D and 3D are presented.