The CFD numerical model is established to study the aerodynamic heating of thermal protection system (TPS) with initial rectangular damage. The high peak heat flux appears on the side walls of the damage area, and the peak heat flux on windward side is greater than that on the leeward side. But the heat flux on the bottom of damage area is very low. The finite element heat transfer analysis models of thermal protection systems with and without damage are established by using the heat flux calculated above. The damage results show that the maximum temperature of tile rises sharply, and it exceeds the ultimate temperature 1 500℃ that tile can bear, so the failure occurs on the tile firstly. But the damage has little influence on the maximum temperature of structure. Finally, damage tolerance analysis on the TPS is conducted. The maximum admissible width of rectangular damage reduces from 22.7 mm to 12.6 mm, and that of arc damage reduces from 34.6 mm to 25.1 mm when the maximum value of external heat flux increases from 100 kW/m² to 140 kW/m² under the ultimate temperature of tile. This is, as the maximum value of external heat flux increases, the maximum admissible width of damage area reduces, and the maximum admissible width of the arc damage is greater than that of the rectangular damage under the same external heat flux level.