The present invention discloses a multi-beamforming optimization method for space-based ADS-B based on a coverage matrix. The method includes: calculating signal-to-noise ratios of received signals based on an ADS-B signal model and an air-space channel model; deriving the correct reception probability of ADS-B signals by a satellite with different signal-to-noise ratios and with different numbers of aircraft on the basis of analyzing a correct decoding probability and a collision probability; and in the case that the constraint of satellite coverage metric is satisfied, aiming at minimizing the update interval of position messages at the update probability of 95%, establishing a digital multi-beamforming optimization model for space-based ADS-B.