The invention discloses an ultralow sidelobe synthetic aperture radar imaging method based on a complete complementary sequence. The ultralow sidelobe synthetic aperture radar imaging method includes steps of 1, dividing echo data based on signal waveforms of the complete complementary sequence into echo data which are obtained by means of utilizing two complementary sequences as radar transmitting signals independently; 2, compressing range pulses based on matched filtering; 3, performing azimuth Fourier transformation; 4, correcting range migratory motion; 5, performing azimuth data high-frequency zero fill; 6, shifting and adding the data after zero rill; and 7, performing azimuth compressing to obtain a final image. The ultralow sidelobe synthetic aperture radar imaging method has theadvantages that radar signal waveforms are easy to be generated, pulse compressing is easy to be realized, azimuth ultralow sidelobe is realized, and azimuth resolution and image quality are high.