An internal wave is a common phenomenon that occurs in the pycnocline of the ocean. Its proprieties are closely related with ocean parameters

such as stratification. An internal wave is normally generated by tidal currents that encounter rough topography at deep ocean. Many internal waves in the South China Sea（ SCS） have been detected from remote images; as a result

research on these waves has become popular in recent years. With the objective of exploring internal wave propagation and accurate inversed internal wave parameters

this study investigates a new model. The NonL inear Schrdinger（ NLS） equation is established in a three-layer stratification configuration fluid as the theoretical model

and the SAR remote sensing detective model is presented based on the NLS equation. The inverse relation of the internal wave parameters is also proposed.The three-layer NLS equation is based on the basic equations of fluid dynamics. Assuming that ocean water is stratified in a three-layer model

the Laplace and Bernoulli formulas of hydromechanics are first used. By introducing the multiple scale and perturbation expansion method

the governing equation can then be transformed into the NLS equation. The analytic solution is also obtained

and the analysis of the physical significance of several parameters in the equation is provided.The internal wave amplitude is inversed in the Dong Sha Atoll of the SCS and the Malin shelf edge of the United Kingdom to verify the accuracy of the model. Inversion results are in accordance with the in situ measurement data. Moreover

the results of the three-layer NLS equation are more accurate than the two-layer models

such as the KdV and two-layer NLS equation. This finding proves that our NLS equation in a three-layer system is suitable for studying internal wave parameters.The three-layer NLS equation is quite close to real ocean conditions. A clear view of internal waves can be obtained with this model. The inversion results show that the three-layer NLS equation is more suitable for studying internal waves in the SCS and Malin shelf areas than the two-layers models.