In view of the current direct sequence spread spectrum underwater acoustic communication has become an important detection object of underwater acoustic non-cooperative communication detection, based on the analysis of the applicability of the current three mainstream underwater acoustic spread spectrum communication detection methods in the offshore complex multipath and low signal-to-noise ratio environment spread spectrum communication detection, a covert communication standard based on time domain autocorrelation detection is proposed, and the conventional energy detection covert standard is extended. At the same time, through simulation analysis, it is found that under the new covert communication standard, M-ary spread spectrum has better covert performance than conventional spread spectrum.