Phenolic foams were prepared by compression molding mixng phenolic resin with hollow phenolic microspheres by different volume ratio, followed by carbonizing at 900 °C under Ar to produce carbon foams composites with hollow carbon microsphere structure. Microstructure of carbon foams were studied. Effect of content of microspheres on compressive properties and fracture toughness of carbon foams were investigated. The results show that compressive fracture characteristics of carbon foams change from gradient-brittle fracture to pseudoplastic with increasing content of microspheres, fracture toughness of which obviously improved for same change. Fracture toughness of CF-80 performs better than others. The specific compressive strength of carbon foams could be improved by increasing content of microspheres properly, and that of CF-70 is up to 43.32 MJ.kg_-1.