Abstract: Bisphenol A-type phthalonitrile/poly (dimethylsilane-m-diacetylenyl phenyl) resin (PBA) was prepared by modifying Poly (dimethylsilane-m-diacetylenyl phenyl) resin (PDMP) with bisphenol A-type phthalonitrile prepolymer (BAPh-P). The curing behavior, viscosity and heat resistance were analyzed by DSC, FTIR, rheological analysis and TGA. The results show that the curing peak temperature of PBA resin is higher than that of PDMP; the curing reaction is mainly Diels alder and addition reaction of alkynyl group, triazine ring and phthalocyanine ring formed by cyano further crosslinking; heat resistance of PDMP in air is improved by the addition of BAPh-P, and temperature with mass loss of 5% (T_d5) of PBA-1 (PDMP: BAPh-P mass ratio of 5∶1) in N₂ and air is 640.6℃ and 591℃, respectively, and mass retention rates at 1000℃ is 89.0% and 26.9%; with the increase of BAPh-P mass, the T_d5 of PBA resin curing compound decreases, but the T_d5 in air is higher than that of PDMP; The bending strength of quartz fiber reinforced PBA resin matrix (QF/PBA) composites increases gradually at room temperature with the increase of BAPh-P mass, and then decreases at high temperature; flexural strength of QF/PBA-2 composite at room temperature and 400℃ is 363 MPa and 330 MPa, respectively, which is higher than that of PDMP, interlaminar shear strength (ILSS) at room temperature and 400℃ is 37.5 MPa and 22.2 MPa, respectively.