Surface catalytic mechanism is dominated by CO₂ recombination during the hypersonic Mars entries, which will highly influence the aerodynamic heating. The surface CO₂ two-step catalytic model was dealt with on the basis of the three-dimensional compressible flow solver for chemical reaction system. The rates of surface chemical reactions were controlled by surface adsorption and Eley-Rideal recombination. The hypersonic flow around the 70° sphere-cone testing model was numerically solved to predict the chemical non-equilibrium aerodynamic heating with surface catalytic effects. The influence of two-step CO₂ catalytic mechanism, including two pathways, CO+O(s) and O+CO(s), on the aerodynamic heating was numerically investigated. The recombination of O₂ and CO₂ coexists and competes with each other. The catalytic heating increases monotonically with the rise of catalytic efficiency. The numerical calculation established a quantitative correlation between the catalytic pathways and the non-equilibrium heating level, and the results show that the relationships between the weight of two CO₂ catalytic pathways and the heating capacity are non-monotonic, and the combined aerodynamic heating of two pathways of CO₂ recombination is calculated to be higher than the value from single pathway. The current study contributes in several ways to our understanding of carbon-oxygen catalytic mechanism and precise evaluation of aerodynamic heating for Mars entries.