Diallylbisphenol A (O-DABPA) was applied to modify the bismaleimide (BMI) resin, which the structure and curing reaction is analyzed by fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) respectively after modification. Prepreg is also prepared based on the modified BMI, and its machanical proerty and bending property under high temperature are investigated. For monolithic laminate made from the prepreg, the results show that the technological properties can be improved and the laminar shearing strength reaches 84.86 Mpa when the mass ratio is 1∶1 of Diallylbisphenol A to bismaleimide (BMI), and the reaction time is 1h under 175 ℃;the bending strength and the modulus is 1326.41 MPa, 120.31 GPa, and the strength retention rate is 76.73% respectively under 240℃.