To address the issues of reservoir pore-throat blockage and permeability decline caused by asphaltene deposition during CO2 flooding in low-permeability reservoirs, this study proposes a novel technical approach utilizing nanomaterials to inhibit asphaltene deposition. Using graphene oxide (GO), aniline, and decylamine monomers as raw materials, modified nano-graphene oxide (GO-BD) was prepared via covalent grafting. Systematic asphaltene dispersion experiments and online CO? flooding experiments based on low-field nuclear magnetic resonance (NMR) were conducted to evaluate its effectiveness in inhibiting asphaltene deposition. The research results show that: The GO-BD prepared after modification of GO exhibits good hydrophobicity; GO-BD possesses excellent performance in inhibiting asphaltene deposition, significantly delaying the onset point of asphaltene precipitation and reducing its aggregate size. At a GO-BD concentration of 25 mg/L, the asphaltene precipitation point of the oil sample increased from 42.03% to 58.27%, and the asphaltene aggregate particle size decreased from 1297 nm to 498 nm; During the CO2 flooding process, compared to injecting pure CO2, adding a GO-BD inhibitor with a mass fraction of 0.8% to the crude oil reduced the core permeability damage rate by 69.8%, decreased the pore blockage rate by 7% to 10%, and increased oil recovery by more than 10%. The research results provide reference and guidance for inhibiting asphaltene deposition during CO2 displacement processes using nanofluid materials.