Potassium Bromide (KBr) is recognized for its performance in improving luminescence intensity and stability of perovskite nanocrystals for white light emitting diodes (W-LEDs). This work establishes a simulation of KBr’s scattering influence of chromaticity and luminosity of the general W-LED model. The concentration of KBr varies to monitor the optical influences. The Mie-scattering and MATLAB computation are the primary simulation means. Results demonstrate the efficacy of increasing KBr amount in reducing the spatial chromatic deviation while minimizing the reduction in luminescence intensity of the W-LED. Thus, KBr owns a great potential to be a promising additive for phosphor compound for the fabrication of high-power and high-quality W-LED devices.