A light emitting device includes a substrate, a plurality of rectifier diodes, and at least one light emitting diode (LED) module. The substrate has a first cavity, a second cavity, and a third cavity formed thereon. The rectifier diodes are arranged in the first cavity and the third cavity respectively. The LED module is arranged in the second cavity. The LED module includes a plurality of LEDs. The light emitting device is capable of rectifying and converting an alternating current (AC) power supply to drive the LEDs to emit light.