The invention discloses an underwater acoustic communication awakening method based on a linear frequency modulation signal, and relates to the field of underwater acoustic communication. The method comprises a sending end and a receiving end, wherein the sending end selects the linear frequency modulation signal as a wake-up signal, and the linear frequency modulation signal has strong frequencyselective fading resistance and good resolution characteristic, so that the awakening reliability under the conditions that a multipath effect of a channel is serious and a signal-to-noise ratio of the receiving end is low is improved. A judgment principle that three is chosen from five is further adopted at the receiving end, the problems of amplitude fading and intersymbol interference caused bythe multipath effect are effectively solved, a missed alarm and a false alarm of awakening are reduced, and the awakening reliability is improved. Meanwhile, an awakening address code between multipoint network communications is constructed at the sending end by utilizing different combination modes of upper/lower frequency modulation, the false alarm probability of awakening can be reduced undera plurality of network nodes, and the awakening stability is improved.