A variable-color accessory is provided comprising: a plurality of accessory surfaces, a light-emitting plate, a light-scattering plate, and a control unit. The light-emitting plate is mounted inside one of the accessory surfaces, where the light-emitting plate is flexible, is bent consistently with one of the accessory surfaces, and has a plurality of light-emitting diodes for emitting different light colors. The light-scattering plate is disposed between the light-emitting plate and one of the accessory surfaces, where the light-scattering plate is flexible and transmits light. The control unit is electrically connected to the light-emitting plate, to control turn-on/off of the light-emitting diodes of the light-emitting plate. A variable-color device applied to the accessory is further provided.