Abstract: In this paper, the ocean acoustic channel is taken as a time-variant channel, and the two-dimensional Wigner-Ville spectrum (TDWVS) of the time-variant channel is used to analyse the conjoint time-shift-frequency-dalay distrubution or the fading and spread statistical characteristics of the channel. The relation between the output and input Wigner-Ville spectrums of the channel is discussed and some examples for the specific channel are shown. Finally, applications on the detection using the WVS and TDWVS are given. The advantage is obvious, when the signal is a linear frequency-modulated signal.