Abstract: Based on the experimental data of a joint geo-acoustic and underwater-acoustic investigation in the South China Sea, this study obtained a layered geo-acoustic model by using migration imaging of multi-channel seismic data and inversion of sub-bottom profile data, and established the reference values and variation intervals of the model. Combined with the measured acoustic parameters in water, this study calculated the sound transmission loss by using the Krakenc coupled mode model for various geo-acoustic parameters, and conducted an analysis on the variation of the root mean square error with respect to the geo-acoustic parameters and the distribution of this error. The results showed 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 a minimal influence on the sound transmission loss. This study studied the influence of geo-acoustic parameters on the sound field in the layered structure of the seabed under an environment close to the real seabed, which provides a basis for establishing the geo-acoustic model in the South China Sea.