Abstract: In order to improve the flame retardancy and fire resistance of room temperature vulcanized (RTV) silicone rubber foam, glass powder and zinc borate as flux agent, and mica powder as refractory filler were used to prepare ceramifiable flame retardant RTV silicone rubber foam. The effects of different types and proportions of inorganic fillers on the micromorphology, thermal stability, flame retardancy and combustion behavior of the silicone rubber foam, as well as the ceramifiable behavior of the silicone rubber foam after ablation at different temperatures were studied. The results show that the introduction of glass powder affects the foaming process of the silicone rubber foam, forming a foam structure with large pore size, which is not conducive to the improvement of the flame retardancy, thermal stability and fire safety performances of the silicone rubber foam. But, glass power can remarkably decrease ceramization temperature of the silicone rubber foam. The introduction of zinc borate greatly improves the flame retardancy, thermal stability in high temperature zone and fire safety performances of the silicone rubber foam. Meanwhile, zinc borate and mica powder show good synergistic flame retardant effect. limiting oxygen index (LOI) value of the silicone rubber foam can reach to 33.2, and it can pass the vertical combustion FV-0 level. Carbon residue of the silicone rubber foam at 900℃ can reach up to 75.9% in thermogravimetric analysis in N₂ atmosphere. The heat release, smoke release of the silicone rubber foam and the mass loss after the ablation experiment are significantly reduced. In addition, zinc borate also contributes to the formation of ceramic carbon residue.