In this paper, a controllable one-step doping method has been successfully adopted in the cesium copper iodide perovskite’s luminescence, a high-quality white-light emission with Commission Internationale de l′Eclairage (CIE) coordinates of (0.3397, 0.3325), and a color rendering index (CRI) reaching up to 90 was realized in a convenient way. Through adding impurities into the ${\mathrm{Cs}}_3{\mathrm{Cu}}_2{\mathrm{I}}_5$ system, high efficiency and stable ${\mathrm{CsCu}}_2{\mathrm{I}}_3$ was synthesized, and the coexistence of varied high luminescence phases realized the white lighting. Strikingly, blue-emitting ${\mathrm{Cs}}_3{\mathrm{Cu}}_2{\mathrm{I}}_5$ and yellow-emitting ${\mathrm{CsCu}}_2{\mathrm{I}}_3$ could coexist, and their respective luminescence was not interacted in the compound, which was beneficial for acquiring a single emission and highly efficient white lighting. This work carried out a deep exploration of the Cu-based metal halides, and would be favorable to the applications of lead-free perovskites.