Well mixed-color distribution of illumination and uniform illuminated environment are the common requirements in color vision applications. Using three-ring light-emitting diode (LED) array and diffuse reflection surface, an indirection method for the uniform illumination is proposed, and a mathematic simulation algorithm is constructed. Based on the Lambertian characteristic of a sing LED, the irradiance distribution over a sphere inner surface to the three-ring LED array is discussed. Then light is reflected to the detected surface by sphere inner surface. The sphere inner surface with high diffuse reflectance can be seemed as a Lambertian surface. According to bi-directional reflectance distribution functions (BRDF) of sphere inner surface, the uniformity of irradiance distribution of detection surface is simulated. Experimentd are implemented to check the validity of simulation results and the indirection method. Some experimental images show uniform mixed-color distribution and the illumination uniformity of 95.5% can fulfill the meets of color vision applications. The experimental results confirm that this method is useful for the uniform illumination design.