The utility model discloses an illuminant water tap with changeable colors, which comprises a water tap main body. A hydraulic generator is respectively positioned in a cold water pipe and a hot water pipe in the water tap main body; the hydraulic generator is connected with a circuit board via an electric wire; the circuit board is connected with a color-changing LED lamp that is installed in the water outlet end of the water tap main body; the light emitted by the color-changing LED lamp mixes with the water flows from the water tap to form an illuminant water flow. The color of the water flow can be changed along with the color of the color-changing LED lamp. Therefore, when in use, the user can judge whether the water is cold or hot according to the color of water flow, so as to prevent the user from being scalded by hot water. Besides, with such design, the water tap, at the background of colorful light, appears more energetic and dynamic, thus realizing excellent decorating effect.