A wheel disc device includes a wheel disc and locking devices. The wheel disc includes an outer cover and a seat. The wheel disc is locked to the wheel frame of a bicycle by locking devices. Illumination devices, audio devices or video devices can be attached to the wheel disc. Therefore, as power is actuated and the bicycle is driven, light cycles with different patterns or audio effects will be emitted. By the present invention, different decorations can be firmly secured to the wheel of a bicycle.