SiCf/SiC ceramic matrix composite is the key material of thermal structural component of turbine. Highly dense KD-II SiC fiber reinforced SiCf/SiC composite was fabricated by melt infiltration of silicon. The microstructure, mechanical properties, thermal properties and oxidation resistance under 1200℃ or above were studied. The porosity of meltinfiltrated SiCf/SiC is only 1.6%. The flexural strength of SiCf/SiC composite at room temperature and 1200℃ are (521±89) and (576±22)MPa, respectively. SiCf/SiC composite shows non-brittle failure characteristic. The thermal conductivities of thickness direction at room temperature and 1300℃ are 41.7W/(m · K) and 18.9W/(m · K). The flexural strength of meltinfiltrated SiCf/SiC composite oxidized for 1000h at 1200℃ is (360±54)MPa, which is only decreased by 19%. The meltinfiltrated SiCf/SiC composite possess excellent oxidation stability, which is promised to be used as thermal structural material in turbine energy.