Abstract: Based on the experimental data of a joint geo-acoustic and underwater-acoustic investigation in the South China Sea, a layered geo-acoustic model was obtained by migration imaging of multi-channel seismic data and inversion of sub-bottom profile data. The reference values and variation intervals of the layered geo-acoustic model are established in this paper. Combined with the measured acoustic parameters in water, the sound transmission loss is calculated using the Krakenc coupled mode model for various geo-acoustic parameters. The analysis was conducted on the variation of the root mean square error with respect to the geo-acoustic parameters and the distribution of this error. The results indicate that for 100 Hz sound source, the sound velocity of the first and second layers in the geo-acoustic model has a significant impact on transmission loss, exhibiting the strongest parameter sensitivity, while the attenuation coefficients and thickness of both layers have a secondary impact on transmission loss. The substrate has minimal influence on the sound transmission loss. In this paper, the influence of geo-acoustic parameters on the sound field in the layered structure of the seabed is studied in an environment close to the real seabed, which provides a basis for establishing the geo-acoustic model in the South China Sea.