Abstract: Relationship among the quantity of hiding data,their invisibility,and robustness of hiding in an image is studied.A binary image and Chinese characters were embedded into a 256 gray-level image with LSB method.The algorithm to hide the data both in single bit-plane and multi-bit-plane of the image are given.Experiments are carried out to hide a binary image into each bit-plane （8bit-planes totally） of the image,and hide Chinese characters into multi-bit-plane （0,0～1,0～2,0～3,0～4,0～5,0 ～6,0～7） of the same image.Attack experiments are also made with noise adding,filtering and JPEG compression.Experimental results show the relationship among the quantity of hidden data,invisibility and robustness for different single bit-plane and different multi-bit-plane respectively.Some suggestions are given about the preferable hiding scheme to meet various application needs.