A data feedback method includes acquiring, by the beamformee, the number of columns from a null data packet announcement (NDPA) message; detecting the number of active first spatial streams; comparing the number of first spatial streams with the number of columns, and taking the smaller value obtained from the comparison as the number of second spatial streams required for feedback; and feeding back the number of second spatial streams and spatial stream measurement information about the second spatial streams to the beamformer.