The samples made from a SiC-C/SiC composite were pretreated in AT under creep, fatigue, creep and fatigue interaction, as well as in dry oxygen and wet oxygen under fatigue at 1300℃for 15 hours. The fracture behaviors of the pretreated samples were investigated at 1300℃. The loading-strain curves and the microstructures of the sample were compared with each other. The various of high temperature tensile behaviors was attributed to the different microstructures resulted from different high temperature pretreatments. The samples made from a SiC-C / SiC composite were pretreated in AT under creep, fatigue, creep and fatigue interaction, as well as in dry oxygen and wet oxygen under fatigue at 1300 ° C for 15 hours. The fracture behaviors of the pretreated samples were investigated at 1300 ° C. The loading-strain curves and the microstructures of the sample were compared with each other. The various of high temperature tension behaviors was attributed to the different microstructures resulted from different high temperature pretreatments.