Based on the relationship between object and image in the holography, variations of image position with both expandings of wavelengbh and reference source are discussed in detail. The idea presented in this papar is that images of whole visible lighb can be overlapped to generate an achromatic image by making use of the one-dimentional diffused reference beam. The achromatic image rango is defined. Having considered the restriction of the elementary hologram and pupil of the eye to imaging beams, the high-quality achromatic image can be observed.