Abstract: The plane elastic modulus of self-healing 2.5D C/SiC composite (2.5D-C/SiC ) were studied by experiment. According to the micro-structure characteristic of composite, the prediction model of elastic modulus of 2.5D-C/SiC was founded. The results agreed with the experiments very well, the model and calculation method were proved to be right. As the parameters, including knit angle of warp, the number of fiber in fiber bundle and the number of layers the warp crossed, increased respectively, the variation tendency of four parameters, including the volume fraction of weft, the volume fraction of warp, the volume fraction of the whole fiber and the elastic modulus, were obtained. As the total volume fraction of silicon carbide and boron carbide was a constant, the variation tendency of elastic modulus was obtained with the ratio of boron carbide and silicon carbide (α) increasing.