The invention relates to a control system and a control method of a light emitting element. The control system comprises a mixer, a separator, a controller and at least one light emitting element. The mixer mixes a power component and a signal component for generating a mixed signal. The separator separates the power component and the signal component from the mixed signal. The controller acts according to the power component and generates at least one control signal according to the signal component. The light emitting element emits light according to the control signal. The invention further provides an electronic device with the control system of the light emitting element, and a control method of the light emitting element.