The gradient refractive index coating overcomes the initial disadvantages of the traditional discrete coating by eliminating the interfaces. A way of designing this kind of coatings is provided. Based on the wavelets theory and the gradient refractive index antireflection theory, with the high-reflection discrete multilayer dielectric coatings as the reference, the design principle with Rugate filters of different type and color filters is presented, and red, blue and green color filters with high spectral performance are designed theoretically according to the targets of color filters used in the rear display system. The angular sensitivity and polarization effect of the new design are compared with the multilayer coating obtained by the traditional high-reflection coating stacking method, and it is found that the former is less sensitive to the incidence angle and exhibits less polarization effect.