In this paper，a new method of hiding gray-images in a host image by using double-random phase encryption method based on kinoform iterative is presented，through which not only the volume to be hidden can be compressed，but also the optical efficiency in the information extracting can be improved. The decoding process of which will not rely on the original host image，and this method can also be applied to the hiding of binary-images. In the last part of this paper，the efficiency and the robustness of this method is analyzed. Computer simulations are presented to illustrate the effectiveness of this method.