As the service temperature of reusable launch vehicles increases, the issue of thermal short circuits in thermal protection system connectors becomes more critical. The current focus is on developing connector materials with low thermal conductivity and high strength. In this study, alumina-silica fiber reinforced alumina-silica ceramic matrix (ASf/AS) composite is fabricated using matrix design and mold-pressing process to achieve the desired properties. By investigating composite materials with bimodal particle size distribution and varying sintering temperatures, the filling efficiency of the matrix within fiber bundles is enhanced and matrix shrinkage during sintering is reduced. The ASf/AS composites achieve a flexural strength of 129.7 ± 5.8 MPa, a tensile strength of 86.1 ± 2.5 MPa, and exhibited low thermal conductivity of 0.415 W/(m·K). Subsequently, ASf/AS bolts are produced following specific design parameters. The strength and failure mechanism of the ASf/AS composites and bolts are examined based on micro-morphology and stress-strain curve analysis. This research offers a promising approach for developing low-thermal conductivity and high-strength connector composite materials for aerospace thermal protection systems.