Abstract: To address the issues of pore formation and poor mechanical properties of photocured alumina ceramics after degreasing and sintering, the effect of graphene addition on the rheology, sedimentation, curing behavior of ceramic slurries, and mechanical properties of sintered body was systematically investigated. γ-glycidoxypropyltrimethoxysilane (KH560) was used for surface modification of Al₂O₃ powders, and different amounts of graphene was added to prepare photocurable slurries with high solid fraction and low viscosity. The slurry formulation and photocuring process parameters were optimized using Fourier-transform infrared spectroscopy, rotational rheometer, sedimentation test, and the Beer-Lambert model. The results show that when the KH560 content is 2.5wt% and the graphene content is 0.01wt%, the slurry exhibits the lowest viscosity and the least sedimentation stratification. Under an exposure time of 4 s, the slurry with 0.01wt% graphene exhibits a transmission depth of 382 μm and a critical exposure energy of 44.3 mJ/cm². After sintering at 1750 ℃, the ceramic parts reach a relative density of 99.7%, bending strength of 27.61 MPa and microhardness of 13.45 GPa. Graphene effectively promotes sintering densification and enhances mechanical properties through steric hindrance and crack deflection mechanisms. This study provides an experimental basis for vat photopolymerization additive manufacturing of highly dense and high-performance alumina ceramics.