Disclosed herein are low-noise multi-output power supply circuits and methods. In one embodiment, a method of controlling a low-noise multi-output power supply circuit, can include: (i) detecting operation states of each of a plurality of switch mode power supplies; (ii) generating a frequency modulation signal to control an operating frequency of a switch mode power supply to be substantially equal to a main frequency signal when the switch mode power supply is detected to operate in a heavy-load steady state; and (iii) controlling the operating frequency of the switch mode power supply to be independent of the main frequency signal when the switch mode power supply is detected to operate in a light-load or a dynamic state.