Abstract: Polyborosilazane with ethynyl group (PBSZ) was synthesized and hybrided with poly(silicon-containing arylacetylene) (PSA) resin to improve thermal-oxidation resistance of polyarylacetylene resin. The structure of PBSZ was characterized by FTIR, NMR and gel permeation chromatography (GPC). The processing properties of PBSZ/PSA resin were investigated by rotational rheometer and DSC, and the thermostability and thermal-oxidation resistance of PBSZ/PSA resin were examined by TGA, SEM and EDS. The results show that PBSZ/PSA resin offers good processability, and could be cured at 210℃ with low exothermal heat. The cured resin residual yields up to 38.0% at 1000℃ under air, and a dense protective layer about 60-80 μm thickness is formed after being oxidized, which inhibits the materials from being oxidized by oxygen. Besides, the sinter of cured resin by 1200℃ also has thermal-oxidation resistance, and a dense ceramic protective layer about 10 μm thickness is produced after being oxidized at 1200℃ and effectively keeps the materials from being oxidized by oxygen.