The biggest problem common on to all forms of Phase Shift Interferometer is unwrapping the phase. Simple phase unwrpping algorithms assume that every pixel is within radianse of its neighbors. If this is true, any resonable algorithm will return the correct unwrapped phase. If not, correct unwrapped phase will not be obtained. in rough surface, frequently, neighboring pixels have phase steps greater than. This paper proposes the mew method which makes phase steps smaller than by sub-pixel step movement.