The CO₂ flooding method is effectively considered to improve crude oil flowability by integrating oil displacement, extraction of crude oil components, and dissolution effects, making it a mainstream EOR technology. However, during this process, the flow rate of CO₂ is generally observed to be significantly higher than that of crude oil, and mass transfer between CO₂ and crude oil is found to alter their compositions, which frequently triggers asphaltene deposition. The mass transfer mechanism and asphaltene deposition characteristics between CO₂ and crude oil from Zhenglizhuang reservoir was researched. When CO₂ dissolution occurred at 32.8 MPa, the initial deposition pressure of crude oil asphaltene was substantially increased compared with the scenario without CO₂ dissolution, indicating higher susceptibility to deposition. During multi-stage CO₂-crude oil contact processes at miscible pressure (32.8 MPa), two phenomena were observed: CO₂ was fully dissolved into the crude oil to gradually increase the gas-oil ratio of the equilibrium oil phase, while light hydrocarbon components (primarily C₁ ~ C₄) were simultaneously extracted from the crude oil by CO₂. This extraction process caused the proportion of heavy components (C₁₀₊) in the crude oil to increase, resulting in larger density of degassed oil. This phenomenon was essentially eliminated after 8 contact stages. The combined effects of CO₂ dissolution and heavy component enrichment were demonstrated to induce asphaltene deposition in crude oil. After 10 contact stages, the asphaltene deposition amount was measured as 0.068 2 g/L through in-situ filtration method. The deposited material contains 87.71% C and 11.68% O, showing close similarity to actual field deposits. Notably, the obtained deposits were observed to be effectively soluble in organic solvents including petroleum ether and carbon disulfide. These findings are considered to provide significant guidance for understanding CO₂ miscible flooding mechanisms in target reservoirs and developing asphaltene deposit removal strategies.