The power of light forward and backward scattered by bubbles in water was predicted by the LambertBeer law,and the formula of SNR was educed. The light backward scattered by water at close quarters was shielded by optical shelter and the power of backward scattered light was measured by a laser power meter,Tne results show that the effect of water scattering on light backscattering properties of bubbles is obvious,and SNR of received signals will be improved if the light backscattered from water at close quarters is restrained.