In the design and simulation of micro/nano device areas, it becomes more and more important to obtain, fast and accurately, transient electric field solutions in combined conductor/dielectric materials. The time characteristics for such transient process vary depending on the electric properties of device. Normally, for conductor/dielectric combined device, the transient signal will last in the order of piso second. We have developed a fast, accurate algorithm, based on the conservation of total current, to simulate transient electric field in combined conductor/dielectric device.