The acoustic scattering problem of underwater shells has long been a subject of sustained concern across multiple fields; it also serves as a foundational basis for target reconstruction within the domain of underwater acoustics. In this presentation, our primary focus lies on the scattering phenomena associated with rough surfaces and shell structures. We first introduce a novel integral equation tailored to address the scattering problem. Subsequently, building on a detailed analysis of the integral kernel, we investigate the numerical methods applicable to this integral equation. We then establish the convergence of the proposed algorithm and present relevant numerical results pertaining to the scattering problems under study. Lastly, we will provide an overview of our ongoing research endeavors.