A novel polyarylacetylene matrix composites reinforced by hollow silica fiber (HSF/ PAA) were fabricated by resin transfer molding (RTM) using hollow silica fiber (HSF) and polyarylacetylene (PAA). The mechanical properties and dielectric properties between the HSF/ PAA composites and SF/ PAA composites were compared in this paper, and so the effects of fiber reinforcement architecture on the mechanical properties. The results show that the HSF/ PAA composites have good high temperature mechanical properties and excellent dielectric property, and that maximum operating temperature of the HSF/ PAA composites is up to 450℃. Besides,it is hopeful to further improve the over-all properties of HSF/ PAA composites by optimizing the fiber reinforcement architecture. Since the low dielectric constant (3. 1) and dielectric loss (0. 004) seem to have excellent stability to a wide temperature and frequency range, the HSF/ PAA composites could be used as high-temperature wave-transparent materials in the aerospace and many other fields, though, the high temperature mechanical properties of the HSF/ PAA composites are only 55 ~75% of the SF/ PAA composites.