Abstract: An efficient method for predicting the acoustic scattering of weakly scattering targets using the Fourier diffraction theorem in reverse is proposed.According to the target shape,the density and sound velocity of the surrounding medium,a three-dimensional image of sound field is constructed,and the relationship between the scattered far field and the image frequency domain samples is established.The directional distribution of scattering field in refined broadband is obtained by taking samples on a spherical surface whose radius is k;in the frequency domain.The numerical results show that Fourier's diffraction theorem is used to solve the acoustic forward problem,which is suitable for solving the scattering sound field of layered,non-uniform and arbitrary shape fluid objects.The far-field sound pressure is obtained by sampling in frequency domain by interpolation method,which avoids the large-scale meshing and iterative computation necessary by 3D-FEM,and can effectively reduce the computational cost and expand the bandwidth of scattering frequency response.The experiment is completed in the water tank of two targets with different acoustic parameters and shapes,the results show that the amplitude function of the directivity of scattered sound pressure was consistent with the theoretical prediction.