Abstract: The compressive behavior of 2.5D C/SiC composite was studied by means of experiment. According to the micro-structure of composite, a new mechanical model was established,the nonlinear stress-strain curves in weft and warp directions were gained. The result shows that, the mechanical behavior in weft direction is different from that in warp direction. As the compressive stress in weft direction increases, the modulus increases, and the compressive strength in weft direction is 270.05MPa. As the compressive stress in warp direction increases, the interlaminar damage occurs, the bending moment caused by compressive stress increases, modulus decreases, and the compressive strength in warp direction is 128.66MPa.