Abstract: The Sound field of a harmonic point source in shallow-water having negative gradient of sound velocity was treated. A monodecreasing sound velocity of sea water was assumed, and the concret form of velocity-depth function was not restricted. Dispersion equation and amplitude of normal modes were derived. From these the numerical solution of a concret problem was easily obtained. The group velocity and attenuation coefficient of normal mode have the simple form, and a better geometrical interpretation may be obtained.