A light-mixing module includes a luminous panel having a plurality of red, green, and blue illuminants arranged alternately, at least one corner being formed in an area defined by the arrangement of the illuminants, a predetermined illuminant being located at the corner; at least one mask located above the luminous panel and over the corner for attenuating the light emitted therethrough from the predetermined illuminant thereunder and having a transmittance preferably lower than 90%; and a light-mixing panel located above the luminous panel and the mask. The light emitted from the illuminants passes through the light-mixing panel for mixture to generate required colored light and then to emit outward. Accordingly, the mask prevents the predetermined illuminant from displaying a weighted color, thus attaining the potency of even light mixture.