Abstract: Sulfonated poly (ether ether ketone) (SPEEK) was obtained by modifying poly(ether ether ketone) (PEEK) with concentrated H₂SO₄. the SPEEK/BBA-BBE-BMI composites were cast-molded, with bismaleimide (BMI) resin as the matrix, 3,3'-diallyl bisphenol A(BBA) and bisphenol A diallyl ether(BBE) as the reactive diluent, SPEEK as the modifier. The effects of SPEEK on the composites were studied. The micro-structure and mechanical properties of the SPEEK/BBA-BBE-BMI composites were examined. The results show that SPEEK produces better modification effect and obvious characteristic peaks of sulfonic acid groups appear in FTIR. SEM and EDS analysis reveale that the micro-structure changes clearly and the content of sulfur element is higher. The micro-structure of SPEEK/BBA-BBE-BMI composite displays that the SPEEK exhibits a porous two-phase structure with a diameter of about 2 μm in the matrix. The "honeycomb" structure changes the fracture morphology from brittle to ductile fracture. The irregular divergence occurre when the breakage encounters the SPEEK component, and this change could supply the composite more excellent properties. The results of mechanical properties for composite indicate that the flexural strength and impact strength of SPEEK/BBA-BBE-BMI composite with 5wt% SPEEK are the best (147.93 MPa and 15.74 kJ/mm²), 49.47% and 66.21% higher than that of the matrix, respectively.