A series of BP resins were prepared by modifying poly(m-diethynylbenzene monomethylhydrosilane) (PSA) with benzoxazine (BZ-BPA) containing cyano and acetylene groups. The curing behaviour of the BP blended resins was analysed by Fourier transform infrared spectroscopy (FT-IR), rotational rheometry, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA): reactive groups such as the oxazine ring, silicone hydrogen bond, terminal acetylene group, internal acetylene group and cyano group were involved in the curing reaction. 5% thermal weight loss of the BP-3 blended resin cures at N2 and air (Td5) and mass retention at 1000 °C were 687.3 °C, 92.1 % and 582.4 °C, 26.5 %, respectively. The mechanical and thermal properties of the quartz fibre reinforced BP resin composites (QF/BP) showed that the flexural strength of the QF/BP composites increased from 153.5 MPa to 300.4 MPa and the interlaminar shear strength increased from 21.6 MPa to 35.6 MPa; the mechanical strength retention of the QF/BP composites was higher than 60 % after 2 h of thermal oxidation at 400 °C The glass transition temperature (Tg) of QF/BP-3 exceeded 500 °C. These results indicate that the BP blended resin and its composites have excellent thermal properties and improved mechanical properties