Abstract: The present application provides a fractional domain noise reduction method for a power signal, including: S1: estimating an optimal fractional Fourier transform angle {circumflex over (?)}0 of an original signal x(t); S2: calculating fractional Fourier transform of the original signal under the optimal fractional Fourier transform angle to obtain X{circumflex over (?)}0 (u); S3: performing band-pass filtering in an optimal fractional Fourier transform domain to obtain X{circumflex over (?)}0 (u)H(u); S4: calculating fractional Fourier transform of X{circumflex over (?)}0 (u)H(u) at an angle of ?X{circumflex over (?)}0 and S5: judging whether {circumflex over (?)}0 is equal to ?/2, if yes, ending the noise reduction, and if no, eliminating a recovered signal component x(t)=x(t)?X{circumflex over (?)}0(u)H(u), and then repeating the steps S1 to S5 again until the estimated optimal FRFT rotation angle is equal to ?/2.