Abstract: To overcome the long-standing bottlenecks of conventional aerogels—limited formability and uncontrollable pore architecture—we report the successful fabrication of polyvinyl alcohol (PVA)/silicon-based nanosheets (SNS)/graphene composite aerogels with a hierarchically porous, loose structure via direct ink writing (DIW) 3D printing technology. Guided by the process requirements of direct-write forming, we designed and optimized a composite printing ink system with high solid content and high viscosity. The results demonstrate that the PSG ink achieves optimal shear-thinning rheological behavior and printing fidelity when the loadings of graphene and SNS are 60 mg and 80 mg, respectively. The SNS are uniformly intercalated between graphene nanosheets, effectively exfoliating the graphene layers and serving as robust structural spacers, which increases the specific surface area and the abundance of micropores. Subsequent removal of the PVA pore-forming agent via water leaching in situ generates a continuous, interconnected pore network enriched with micropores and mesopores throughout the aerogel. This hierarchical porous structure extensively exposes the hydrogen storage active sites of both SNS and graphene, effectively widens ion transport pathways, and markedly accelerates hydrogen ion migration kinetics. As a result, the hydrogen storage dynamic performance of the material is greatly enhanced, with a maximum hydrogen diffusion coefficient reaching 7.53×10⁻⁶ cm² s⁻¹. Density functional theory (DFT) calculations reveal that the composite system exhibits stronger hydrogen adsorption energies compared to its single-component counterparts. The system features both shallow potential wells and an ultrasmooth potential energy surface, thereby preserving exceptional diffusion kinetics. Experimental evidence confirms that the integration of 3D-printed hierarchical loose structure, water-leaching PVA pore engineering, and the synergistic coupling between SNS and graphene substantially optimizes the pore structure and hydrogen storage performance of carbon-based aerogels. This work endows PSG composite carbon aerogels with outstanding hydrogen storage performance, providing an efficient green fabrication strategy and theoretical foundation for the rational design and controllable synthesis of high-performance, structure-tunable porous hydrogen storage materials.