Two-dimensional materials have been widely used to tune the growth andenergy-level alignment of perovskites. However, their incomplete passivationand chaotic usage amounts are not conducive to the preparation of high-quality perovskite films. Herein, we succeeded in obtaining higher-quality CsPbBr₃ films by introducing large-area monolayer graphene as a stablephysical overlay on top of TiO₂ substrates. Benefiting from the inert andatomic smooth graphene surface, the CsPbBr₃ film grown on top by the vander Waal epitaxy has higher crystallinity, improved (100) orientation, and anaverage domain size of up to 1.22 μm. Meanwhile, a strong downward bandbending is observed at the graphene/perovskite interface, improving theelectron extraction to the electron transport layers (ETL). As a result,perovskite film grown on graphene has lower photoluminescence (PL)intensity, shorter carrier lifetime, and fewer defects. Finally, a photovoltaicdevice based on epitaxy CsPbBr₃ film is fabricated, exhibiting powerconversion efficiency (PCE) of up to 10.64% and stability over 2000 h in the air.