Abstract: Rupture life of 3D C/SiC composites was investigated through a simulated combustion windtunnel system,and the effects of temperature (1 200-1 500℃) and stress (100,240 MPa) on rupture life of the composites the enhancing of were also discussed.The results indicate that with the increase of temperature,rupture life of the composites was prolonged due to the three factor effects of the state change of the internal stress,the sealing of the matrix cracks by the SiO2 and the narrowing of the cracks.With the increase of the stress,the width of the matrix cracks in the composites broadened,and the quantity of the cracks increased,which resulted in a more severe damage and a shorter rupture life of the composites.