Carbon fibers-reinforced plastics (CFRPs) are widely used as reinforcing materials in high performance composites. In this work, CFRPs are studied in the addition of SiC treated by different acidic solutions, in order to improve the mechanical interfacial properties of the composites. The effect of chemical surface treatment on SiC has been studied in terms of surface energetics and fracture toughness of the CFRP/SiC composites. According to contact angle measurements, it is observed that SiC does lead to an increase in surface free energy. For the CFRP/SIC system, a direct linear relationship is shown between the surface energetics and the critical stress intensity (KIC) measured by single edge notched beam fracture toughness tests. From the surface energetic point of view, it can be found that the chemical surface treatment is possibly suitable for SiC to be incorporated in fibers and organic matrix. And, a good wetting plays an important role in improving the degree of adhesion at interfaces among fiber-SiC-matrix of the resulting composites.