A light-emitting device is capable of receiving a first voltage signal, a second voltage signal, and a third voltage signal in sequence. The light-emitting device includes a first light-emitting unit, a second light-emitting unit, and a switching. The first voltage signal, the second voltage signal, and the third voltage signal is configured to introduce a first current signal, a second current signal, and a third current signal, respectively. The light-emitting device is configured to emit a first light when introducing the first current signal, the second current signal, and the third current signal. The light-emitting device is configured to emit a second light when introducing the second current signal and the third current signal. The light-emitting device is configured to emit a third light when introducing the second current signal.