Objective To explore the ultra high temperature ceramic （UHTCs） thermal protection design requirements for a sharp–edge vehicle. Methods The aerodynamic thermal environment of hypersonic velocity typical sharp edge vehicle under laminar conditions was researched through FVM based on computational fluid mechanics. The thermal protection design limits were identified through surface heat flux and radiative equilibrium temperature distribution analysis at different angles of attack. For the nose UHTCs thermal protection design of a typical sharp edge vehicle, the nose length and angle of attack effects were studied. Finally, effects of high thermal conductivity on heat protection design of UHTCs were discussed. Results The high heat flux only concentrated in a small region near the stagnation and the heat flux increased obviously with the increase of attack an-gle in the windward. Considering the thermal requirement, the maximum angle of attack was in proportion to the nose length, for example, the limited angle of attack would increase 10o when the nose length increased by 0.1m. Thermal conductivity of the UHTCs had significant influences on the temperature distribution, and the maximum tip temperature of the nose would drop by 205K while the maximum temperature of the structural material would be increased by 50K when the thermal conductivity of the UHTC was increased by 50%. Conclusion The critical limit of UHTCs sharp nose thermal protection design is the structural material temperature which is connected with the UHTCs nose. During design, the angle of attack during flight should be optimized properly and material of proper thermal conductivity should be selected.