Abstract: Hypersonic flow over a compression corner with ablation of heat shield made of graphite is numerically simulated through solving the Navier-Stokes equations of thermochemical nonequilibrium flow coupled with the ablating boundary condition, and the effects of the wall conditions on the flowfield properties are investigated. Sixteen chemical species (N₂, O₂, NO, N, O, NO⁺, N₂⁺, O⁺, N⁺, CO, CO₂, C, C₂, C₃, CN, e^-) are considered, the two-temperature model is taken to describe thermal nonequilibrium. The oxidation and sublimation of C, as well as the recombination of O catalyzed by C are considered at the wall surface. The hypersonic flow over 15°, 18°, 24° compression corners are calculated with Mach number varied from 10 to 30 and total enthalpy from 6 to 55 MJ/kg. Both ablating and non-ablating surface condition are used to investigate the effects of ablation. The flow structure, the characteristics of shock-boundary-layer interaction, the separation properties, and the distribution of the thermochemical properties are analyzed. The results show that the possibility of flow separation and the separation range become larger as the corner angle increases, while smaller as the free stream Mach number rises. Compared with the cases with low-temperature wall, the flow separation zones are lager with ablating wall or with high-temperature wall in radiation equilibrium, and this leads to the positions for peak values of pressure, skin friction and heat flux move downstream.