An initially uncharged droplet suspended in another immiscible fluid under the influence of a steady non-uniform electric field may experience deformation, migration and bursting. This work numerically investigated the behavior of the droplet. Both the droplet and the suspending fluid are assumed as leaky-dielectric or perfect-dielectric. We used a threedimensional spectral boundary element method which has been validated by comparing with other numerical results and experimental findings for droplet deformation in a uniform electric field. The electric properties of the fluids are found to have a big influence on the droplet migration direction and speed in a non-uniform electric field. We have investigated the droplet deformation and motion affected by permittivity ratio, resistivity ratio, viscosity ratio and the electric capillary number in a non-uniform electric field.