A kind of making real-color rainbow hologram with single-wavelength and single-beam are presented. First make three films of rainbow encoded. Then by making use of the image processing software the color image will be divided into red ,green and blue three colors images , and input the LCD liquid crystal screen as the masks. Finally make real-color rain- bow hologram with single-beam. Contraposition difficulties for three dividing colors with traditional method and the tedious procedures to creating dividing colors are resolved. The experimenta results are given.