A novel method for making color rainbow hologram of 3D object has been proposed. Theoretical analysis has indicated that the grating struction of holograms shot by three color object points in same situation is equivalence to those shot by three monochrome object points in different proper situation when satisfying some given conditions. Combining the technique of rainbow hologram,it has studied the coding way of the information distribution for trilolor light on the hologram plane,the hologram algorithm and color hologram facture with monochromatic light,at the same time,it has worked out a satisfying solution to the problem of hologram superposition and color crosstalk. The feasibility and efficiency of the method are confirmed by experimental results.