A novel lightweight tetrafunctional vinyl polysilsesquioxane (TV-DDSQ) was designed and synthesized as a crosslinking-modifier for vinyl liquid silicone rubber (SR) to form a denser cross-linked network structure and introduce a high-temperature resistant cage structure to obtained TV-DDSQ/SR resistance to high temperature oxidation combustion-ablation resistance composites (TV-DDSQ/SR). Compared to SR, 1 phr TV-DDSQ/SR exhibits good resistance to high temperature oxidation combustion (vertical combustion test to UL-94 V0) and excellent ablation properties (21.2 % reduction in linear ablation). The mechanism of ceramization transition of TV-DDSQ/SR under high temperature oxidation combustion and ablation resistance was investigated.