With the rapid development of high-technology fields, advanced aerogel acts as the thermal insulation materials under high-temperature environment attracted extensive attention. Polymer derived ceramic (PDC) aerogels were considered to be a promising thermal protection materials due to its low density, high porosity, excellent thermal insulation performance and high-temperature stability. Silicon oxycarbide (SiOC) ceramic aerogels, one kind of typical representative PDC materials, were mainly formed by partial substitution of C atoms for O atoms in SiO2 tetrahedra. Compared the traditional silica aerogels, silicon oxycarbide (SiOC) aerogels exhibited better thermal and chemical stability as well as higher mechanical strength. Previously research reported that SiOC aerogels were mainly prepared by sol-gel method and PDC route, exhibited a higher density, which limited its applications and development in lightweight thermal insulation filed. Moreover, the obtained SiOC aerogels exhibited a necklace-like structure, poor high-temperature stability and mechanical strength due to the weak contact between nanoparticles. And most researches on SiOC aerogels focused on its high-temperature pyrolysis behavior. In this paper, a lightweight and high-strength SiOC aerogel were prepared using polyhydromethylsiloxane (PHMS) as precursor and tetramethyltetravinylcycletetrasiloxane (D4Vi) as crosslinker through solvothermal, freeze casting and pyrolysis. The influence of D4Vi content on the microstructure and thermal stability of SiOC aerogels were discussed. The evolution of phase composition, mechanical strength and thermal insulation performance was further explored via high-temperature heat treatment and oxidation treatment.