A series of BP resins were prepared by modifying poly(m-diethynylbenzene monomethylhydrosilane) (PSA) with benzoxazine (BZ-BPA) containing cyano and acetylene group. The curing behaviour of the BP blended resins was analyzed by Fourier transform infrared spectroscopy (FT-IR), rotational rheometry, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).The results show that the reactive groups such as oxazine ring, silicone hydrogen bond, terminal acetylene group, internal acetylene group and cyano group were involved in the curing reaction. The 5% thermal mass loss of the BP-3 blended resin in N2 and air (Td5) and mass retention at 1000 °C are 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) show that the flexural strength of the QF/BP composites is 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 is higher than 60 % after 2 h of thermal oxidation at 400 °C;the glass transition temperature (Tg) of QF/BP-3 exceeds 500 °C. These results indicate that the BP blended resin and its composites have excellent thermal properties and improved mechanical properties.