This study examines the impact of varying wind and wave levels on the radar cross section (RCS) analysis of ship targets at different sea surfaces. A ship model was established and the far-field single station RCS of ship targets was analyzed under various sea conditions using a hybrid algorithm of physical optics and moment method (PO-MOM). The study utilized FEKO software to simulate and calculate the far-field single station RCS of the European Buffalo class hovercraft, while also improving the hovercraft model to account for seawater. Additionally, the study analyzed and studied the target RCS of the ship under different sea conditions using the PO-MOM hybrid algorithm, and ultimately utilized the CSI algorithm to compensate for it. The findings indicate that as the sea level rises, the ship's RCS decreases.