<p>This study investigates the hydrodynamic characteristics of an eccentric multi-cylinder system composed of a porous outer cylinder and multiple inner cylinders, based on linear potential flow theory. A semi-analytical model is developed using the eigenfunction expansion method, and its accuracy is validated against existing theoretical and numerical results. The findings reveal that the wave loads on the inner cylinders are highly sensitive to the porosity, spacing, and radius ratio. The underlying mechanisms involve energy dissipation, interference modulation, and geometric shielding, which collectively govern wave focusing, load variation, and energy attenuation within the system. Moreover, the arrangement and permeability of the inner cylinders play a crucial role in mitigating wave concentration and suppressing water accumulation in the gaps, thereby offering valuable implications for structural optimization. This work provides new insights into the hydrodynamic mechanisms of eccentric multi-cylinder systems and offers theoretical guidance for coastal protection, wave energy utilization, and offshore foundation design.</p>