The present invention provides a control circuit for a multi-channel power converter to save power at light load. The control circuit comprises a modulation circuit and an oscillation circuit to modulate the switching frequency of switching signals for power saving. The modulation circuit generates a modulation signal in response to a first feedback signal and a second feedback signal. The oscillation circuit is coupled to the modulation circuit to control a switching frequency of switching signals in accordance with the modulation signal. The switching frequency of the first switching signal can be linearly decreased in response to the decrease of the load when the second switching signal is enabled. The first switching signal can be bursted for further power saving once the second switching signal is disabled.