In order to search a backward optical method for ship wake detection, the influence of wake bubbles on backscattering signal of laser pulse in water is studied. Firstly, based on Fournier Forand volume scattering function, the influence of short-distance bubbles on laser pulse′s backscattering signal in water is analyzed. Secondly, using blue-green laser pulse as light source, the influence of imitated bubbles on laser pulse′s backscattering signal in water is studied experimentally. The results show that, because of wake bubbles, back scattering signal′s leading edge moves left, and its trailing edge moves right. Moreover, the broadering of its width, enhancement of its energy and the increase of its peakvalue also happen, and its position moves left in time-domain. Finally, according to the result, a backward detection method for ship wake bubbles is presented on the basis of the characteristic′s variation of laser pulse′s backscattering signal.