The increasing flight speed of high-speed aircraft imposes stringent demands on the performance enhancement of radomes (antenna windows). To address these requirements, the composites with excellent heat resistance and wave-transparent properties have been developed. The silylene-acetylene copolymer resins (ETSA-MP-MH) were synthesized via Grignard process and subsequently employed to fabricate quartz fabric ( QF)-reinforced composites (QF/ETSA-MP-MH) through hot-press molding in this study. The structure and properties of both copolymers and composites were systematically investigated. The results show that the two silanes, methyldichlorosilane and methylphenyldichlorosilane can copolymerize with Grignard reagent of acetylene to form the copolymer resins, which exhibit solubility in common polar solvents. The initial curing temperature of the copolymer resin decreases with increasing content of Si-H groups in the backbone. The thermal stability of the cured copolymer resin in N₂ and air increases with the increase of phenyl side groups in the copolymer backbones. The temperature of 5% mass loss (T_d5) and residual yield at 800 ℃ (Y_r800) of the cured resin in N₂ and air can reach 536 ℃ and 87.5% , 539 ℃ and 51.6% , respectively. The glass transition temperature (T_g) of QF /ETSA-MP-MH composite are higher than 470 ℃. The loss factor of the composite exhibits below 0.01. The dielectric constant of the composite decreases with the increase content of phenyl side groups in the copolymer backbones, and is as low as 3.5 in the frequency range of 10⁴~ 10⁷ Hz. The mechanical properties of the composites can be improved by increase of phenyl side groups in the backbones and QF pretreatment with coupling agent. The flexural strength and flexural modulus, and interlamellar shear strength of the composite can reach 141 MPa,15 GPa and 11.8 MPa, respectively. These findings highlight the silylene-acetylene copolymers as promising resin matrices for highly heat-resistant and wave-transparent composite, which can be applied in the fields of aerospace and electronic information systems requiring extreme heat resistance and electromagnetic transparency.