Based on ocean internal wave Synthetic Aperture Radar（SAR） imaging mechanism and the M4S model

which was applied to simulate the oceanic features of ocean surface

one new method for retrieving internal wave surface currents from SAR image is introduced.Firstly

accordingto the AH linear theory

the first guessed surface currents could be estimated from the normalized radar crossing section（NRCS） of the internal wave profile in SAR image

and the signal induced by internal wave surface currents can be simulated by M4S.Then the wind speed and internal wave surface currents gradients are modified using the dichotomy method step by step

which causes the simulated signal close to the NRCS measured from SAR image.Finally

the wind speed and the surface currents could be retrieved until a satisfied match between the simulated signals and SAR images.This method is tested on three ERS-2 SAR images in the South China Sea.The results show that the simulated internal wave signal is consistent with the NRCS of internal wave SAR images.Their correlation coefficients are up to 90%

which indicate that this method is convergent and applicable.