A signal quality control method, wherein the method is applied to a base station (1500, 1600) having a plurality of antennas, the base station (1500, 1600) uses the plurality of antennas to send a first time-domain signal set, so as to send L flows, and the method comprises: determining, by the base station (1500, 1600) based on a clipping threshold corresponding to each of the plurality of antennas, a time-domain noise signal for clipping a first time-domain signal of each antenna, the first time-domain signal set is based on the first time-domain signals of the antennas; performing time-frequency transformation on the time-domain noise signal of each antenna to obtain a first frequency-domain noise signal; processing the first frequency-domain noise signals of the plurality of antennas jointly to decompose the first frequency-domain noise signals into a second frequency-domain noise signal set in L flow directions and a third frequency-domain noise signal set in a complementary space of the L flows; and using the second frequency-domain noise signal set and the third frequency-domain noise signal set to clip the first time-domain signal set, wherein the using the second frequency-domain noise signal set and the third frequency-domain noise signal set to clip the first time-domain signal set comprises: weighting the second frequency-domain noise signal set based on a modulation scheme of each of the L flows, and weighting the third frequency-domain noise signal set based on a weight of the complementary space of the L flows, to obtain a fourth frequency-domain noise signal set; and performing time-frequency transformation on the first time-domain signal set to obtain a first frequency-domain signal set, and using the fourth frequency-domain noise signal set in frequency domain to clip the first frequency-domain signal set; or performing frequency-time transformation on the fourth frequency-domain noise signal set to obtain a fourth time-domain noise signal set, and using the fourth time-domain noise signal set in time domain to clip the first time-domain signal set. determining, by the base station (1500, 1600) based on a clipping threshold corresponding to each of the plurality of antennas, a time-domain noise signal for clipping a first time-domain signal of each antenna, the first time-domain signal set is based on the first time-domain signals of the antennas; performing time-frequency transformation on the time-domain noise signal of each antenna to obtain a first frequency-domain noise signal; processing the first frequency-domain noise signals of the plurality of antennas jointly to decompose the first frequency-domain noise signals into a second frequency-domain noise signal set in L flow directions and a third frequency-domain noise signal set in a complementary space of the L flows; and using the second frequency-domain noise signal set and the third frequency-domain noise signal set to clip the first time-domain signal set, wherein the using the second frequency-domain noise signal set and the third frequency-domain noise signal set to clip the first time-domain signal set comprises: weighting the second frequency-domain noise signal set based on a modulation scheme of each of the L flows, and weighting the third frequency-domain noise signal set based on a weight of the complementary space of the L flows, to obtain a fourth frequency-domain noise signal set; and performing time-frequency transformation on the first time-domain signal set to obtain a first frequency-domain signal set, and using the fourth frequency-domain noise signal set in frequency domain to clip the first frequency-domain signal set; or performing frequency-time transformation on the fourth frequency-domain noise signal set to obtain a fourth time-domain noise signal set, and using the fourth time-domain noise signal set in time domain to clip the first time-domain signal set. weighting the second frequency-domain noise signal set based on a modulation scheme of each of the L flows, and weighting the third frequency-domain noise signal set based on a weight of the complementary space of the L flows, to obtain a fourth frequency-domain noise signal set; and performing time-frequency transformation on the first time-domain signal set to obtain a first frequency-domain signal set, and using the fourth frequency-domain noise signal set in frequency domain to clip the first frequency-domain signal set; or performing frequency-time transformation on the fourth frequency-domain noise signal set to obtain a fourth time-domain noise signal set, and using the fourth time-domain noise signal set in time domain to clip the first time-domain signal set.