Abstract: The disclosure provides a light emitting device including a power conversion circuit configured to provide a power voltage, a light source module receives the power voltage, a driving circuit, and a control circuit. The driving circuit is configured to drive a plurality of light emitting units in the light source module and detect a current value flowing through each light emitting unit to generate a current signal. The control circuit is coupled to the power conversion circuit, the light source module, and the driving circuit and is configured to detect a cross-voltage of at least one of the light emitting units. The control circuit calculates a voltage offset value according to a difference between the cross-voltage and the power voltage to generate a control signal according to the voltage offset value and the current signal to accordingly control the power conversion circuit to adjust the power voltage.