The one-dimensional theoretical model of internal solitary waves has been widely used in their prediction. However, on one hand, these theoretical models usually rely heavily on temperature and salinity data when calculating wave functions, which requires the use of moorings equipped with temperature and salinity observation instruments, resulting in high observation costs. On the other hand, they tend to have large prediction errors in complex current environments, such as lower accuracy in calculating the nonlinear phase speed and wave function of internal solitary waves. In this study, a Velocity-Gaussian Function Model was proposed, which reversed the amplitude and wave function of internal solitary waves based on the measured current velocity of the upper layer of the South China Sea from a single mooring. Furthermore, key parameters such as wave-induced current and nonlinear phase speed of internal solitary waves were calculated using a one-dimensional theoretical model. By comparing the measured data from the moorings with the results calculated by the Velocity-Gaussian Function Model, it was found that the model can simulate the wave-induced current throughout the entire water depth by inputting only the measured current velocity from the upper 150 meters of the ocean. Additionally, the error in the nonlinear phase speed can be controlled within 10% compared to the measured value. The application of the Velocity-Gaussian Function Model enables accurate prediction of internal solitary waves in the complex South China Sea, without the need for moorings equipped with temperature and salinity observation instruments, thus significantly reducing the cost of internal solitary wave observation.