A numerical analysis of the surface acoustic waves (SAW), Leaky surface waves has been performed. A method of search for SAW and Bulk waves in crystals is based on the Farnell's technique. A method of search for leaky waves in crystals is based on the calculation of permitted orientations for exceptional bulk waves, which satisfy the stress-free boundary conditions for surface waves. A search for leaky waves is based on the calculation of the Global Extremum of complex boundary condition function, depending on many variables, over the regular grid in combination with local search by Hooke's and Jeeves' method of configurations and by Mugel's procedure in the ravin domains. The optimal characteristics have been found for leaky waves: velocity V, electromechanical coupling coefficient K2, the power flow angle PFA0, attenuation loss (alpha) , the temperature coefficient of delay in LiNbO3, LGS and LGN crystals.