Abstract: The carbon fibers and nitride silicon particles reinforced fused silica composite was fabricated using hot Pressing method. The fused silica matrix is mostly amorphous except for a little amount of tridymite precipitated. The flexural strength value of 113.7MPa, and the fracture toughness value of 1.53MPa·m^1/2. Show the reinforced effects to be very obvious.The addition of some Si₃N₄ particles retards the oxidation of carbon fibers and increases the burning-erosion resistance.Result of simulation carried out on the ground shows that such composite can meet the requirements for application to some spaceflight parts.