Aiming at the shortcomings of laser point to point communication,the assumption of building the communication networks by laser diffusion from sea surface is proposed so that the characteristics of the scattered field of laser from the PCS is studied.Firstly,the 3D model of incident laser beam is established with 3D tapered wave.Secondly,the coupling relationships among components in different directions are analyzed and the corresponding matrix equations are calculated with FBM/SAA.Finally,the 3D BSC is given to accurately express the characteristics of laser diffusion from the PCS.That will make contribution for the further study about the characteristics of laser diffusion from sea surface.