The present disclosure relates to a method for reducing power consumption, including: connecting one terminal of each capacitor in a first and a second capacitor array of an SAR ADC to a first reference voltage via a corresponding primary switch, connecting the other terminal of the capacitors to a positive-terminal analog input signal and a negative-terminal analog input signal respectively via a corresponding multiplexer to complete sampling; determining a value of a most-significant bit by comparing an output voltage of the first capacitor array with an output voltage of the second capacitor array, maintaining or adjusting a reference voltage connected to the other terminal of each capacitor according to the value of the most-significant bit, and determining values of a second-most-significant bit and a least-significant bit by comparing the output voltage of the first capacitor array with the output voltage of the second capacitor array.