Abstract: Two-dimensional layered metal-halide perovskites possess exceptional electronic and optical properties along with remarkable stability, making them a highly promising class of organic–inorganic hybrid semiconductor materials. Owing to their multi-quantum-well structure and high refractive index, effective light management is crucial for optimizing the performance of two-dimensional perovskites. This study utilizes the trapping effect of periodic nanostructures to effectively modulate the light-absorption capacity of two-dimensional perovskites. The theoretical efficiency of two-dimensional perovskite solar cells is systematically analyzed using the finite-difference time-domain method, with a particular focus on the influences of the lattice arrangement, structural morphology, and geometric parameters. Furthermore, we elucidate the underlying mechanism of light management by periodic nanostructures in two-dimensional perovskites and establish the structure–property relationship between nanostructures and light-absorption performance. These findings offer crucial theoretical insights that can guide the enhancement of the performance of perovskite photovoltaic devices.