The invention relates to a power supply control method of a linear power supply, particularly to an ultralow ripple wave circuit control method and device A feedback module of the device detects a linear power supply output end signal and outputs a feedback signal to an adjustment module, and a feedforward module detects a linear power supply input end signal and outputs a front end adjustment signal to the adjustment module; the adjustment module performs adjustment according to the feedback signal provided by the feedback module and the front end adjustment signal provided by the feedforward module, and outputs a switching tube control signal; the adjustment module includes an adder and a signal processor, the adder superposes the feedback signal output by the feedback module and the front end adjustment signal output by the feedforward signal, and outputs the signals to a switching tube control end after amplification through the signal processor; a switching tube controls the on-off degree of the switching tube according to a switching tube control voltage signal output by the adjustment module; and a linear power supply input end signal input to the feedforward module is adjusted, and is output to the adder, and output ripple waves are reduced.