A control circuit for an interleaved switching power supply having a plurality of parallel coupled power stage circuits, can include: a feedback circuit that receives an output voltage of the interleaved switching power supply, and generates an output voltage feedback signal; a ripple generator that receives a plurality of switching control signals, and generates an AC ripple signal having a frequency that is N times a switching frequency; an adder circuit that adds the output voltage feedback signal with the AC ripple signal, and generates a superposition signal; a comparison circuit that receives the superposition signal and a reference voltage, and generates a comparison signal; and a frequency divider circuit that divides the comparison signal into a plurality of turn on control signals configured to control turn on of a plurality of main power switches in the plurality of power stage circuits.