Abstract: The Al₂O₃ and SiO₂ were obtained by sol-gel method and the KH560-Al₂O₃@SiO₂ were prepared with KH560 as the coupling agent. The KH560-Al₂O₃@SiO₂/MBMI-EPN composites were prepared by in-situ polymerization, using bismaleimide resin and phenolic epoxy resin (MBMI-EPN) as matrix, KH560-Al₂O₃@SiO₂ as the reinforcement and 4’4-diaminodiphenylmethane (DDM) as curing agent. The micro-structure of KH560-Al₂O₃@SiO₂ were characterized and the effect of the reinforcement on properties of composites were studied. The results show that the Al₂O₃@SiO₂ particles have clear core-shell structure. The short-fiber Al₂O₃ is inner core, and the amorphous SiO₂ is outer shell, which are connected by chemical bonds. The KH560 is successfully grafted onto the surface of Al₂O₃@SiO₂, and the particles packing phenomenon is weakened. The micro-structure of the composites shows that KH560-Al₂O₃@SiO₂ forms a multi-phase structure in the MBMI-EPN matrix with good dispersion and stable interface. The cross-sectional shape is fish scale, and there are no Al₂O₃@SiO₂ nanoparticle agglomerates and the overall structure is regular. When the content of KH560-Al₂O₃@SiO₂ is 1.5wt%, bending strength and impact strength of the composites are 126 MPa and 14.7 kJ/m², which are 21.2% and 27.8% higher than resin matrix, respectively. And the thermal decomposition temperature of the composites is 392.3℃, which is 14.5℃ higher than that of resin matrix.