[PERSON] [11] proposed the spectral superposition method based on the work of [PERSON], who decomposed the waveguide Green's function into the plane wave spectrum, including the discrete and continuous spectra, which is, both normal and side waves. [PERSON] and [PERSON] [12] studied the analytical solution for the acoustic scattering field that is caused by a spherical target near a single interface using the image method. In recent years, scholars from various countries have proposed some methods for solving both sound scattering and radiation to obtain accurate results efficiently with a small amount of calculation. [PERSON] [13] combined the edge source integral equation with the BEM to deal with the problem of sound scattering in the free field, which greatly reduced the number of calculations. [PERSON] [14] combined the difference time-domain method with far-near field transfer theory to deal with the problem of elastic wave scattering of three-dimensional targets. [PERSON] [15] combined the FEM with normal modes to study the acoustic field of complex targets in a channel, effectively predicting the acoustic scattering field. [PERSON] [16], considering the reflections between the target and the seabed, proposed a hybrid method to calculate the scattering problem of the buried elastic shell target combining the virtual source method and spectral integration to deal with the scattered sound field in the layered medium. [PERSON] [17] calculated the scattered sound field of a series of cylinders. [PERSON] [18] applied the equivalent element method to calculate the sound field scattered by the target in the axisymmetric shallow sea waveguide. [PERSON] [19] studied the ocean bottom scattering sound field in multi-layered media. [PERSON] and [PERSON] [20] used the radiation of a virtual source instead of the target sound scattering to solve the target scattering sound field in the shallow ocean waveguide, but this method can only calculate the low-frequency shallow target. When considering the deep-sea conditions, the influence of the sea surface on the elastic target's impedance decreases when the elastic target is far from the sea surface. In this study, through the acoustic scattering simulation in the free field, the acoustic scattering field is equated to the radiation field of a directional point source; then, the directional point source is placed in the marine environment using ray acoustic to calculate the distribution of the scattering field. This method considers the multiple complex coupling effects between the elastic structure and marine environment. Accurate and reliable calculation results can be obtained when the elastic structure is far from the ocean boundary; this method only performs finite element coupling calculations under free field conditions, greatly reducing the amount of mesh and significantly improving the calculation efficiency as compared with performing finite element calculation in the entire channel. This method combines short-range finite element calculation with the acoustic ray calculation in the long range and it can realize the rapid calculation of the large-scale acoustic scattering field in the complex marine environment.