Abstract: We have derived the integral expression for acoustic held due to a point source in shallow water while sediment is either a liquid or a solid.The synthetic full waveforms are simulated using real axis integration and FFT method.The effects of the sea sediment parameters and center frequency of the source on the low frequency acoustic wave propagation in shallow water are investigated.We may draw a conclusion that the wave groups received in far field are those of the mode waves of the center frequency of source.Finally we have discussed the possibility for inversely deducing the compressional and shear sound speeds of a sediment using the least square optimum through the measured group velocities of a selected mode at different frequencies.