Abstract: Comparing with the on-site coring, geoacoustic inversion method is an effective and economical way for seabed sediment classification. In recent years, we proposed the slope of bottom loss versus grazing angle Fdb (dB/radian) as the single parameter to describe the characteristics of sea bottom. The establishment of single parameter model in thermocline condition provides a new way for the single parameter inversion. Based on this model, a geoacoustic inversion method is proposed. In this paper, the single parameter model in thermocline shallow water is introduced firstly, and then the transmission loss inversion method is proposed for the single parameter inversion. Finally, the applicability of inversion method in thermocline shallow water is proved by experimental data.