A novel curable liquid polysilane (CLS) containing reactive unsaturated bond and Si-H was synthesized from dichloromethylvinylsilae, methyldichlorosilae and Na in presence of 18-crown-6 under sonication at relatively lower temperature and its structure was characterized by FT-IR, 1H-NMR. The cure behavior of CLS was investigated by DSC,FTIR. Thermal stability of cured CLS was examined by TGA. The results showed that the cured polysilane exhibits good anti-oxidation performance under high temperature. And the sinted CLS exhibited high temperature resistance and good ceramic formability.