Polyimide (PI) synthesized from aromatic diamine and dianhydrides via two-step poly-condensation method was highly soluble in TGDDM (MY-720) and DGEBA (E-51) at desirable temperature.TGDDM-PI (M-PI) and DGEBA-PI (E-PI) composites within 0.5％-3％ PI loading could be prepared without organic solvent.On the cryogenically fractured surfaces of M-PI and E-PI composites,no obvious heterogeneous phase was observed by SEM.The mechanical properties were promoted significantly by PI,especially for impact strength.Adding 2％ PI-2W into MY-720 and E-51 composites,the impact strength increased to 21 and 51 kJ/m2,the tensile strength increased by 62％ and 19％,and the flexural strength by 18％ and 13％,respectively,with slight increases in tensile modulus.These results were related to the promotion in plasticity of composites and changes in fragile→ductile fracture mode.Moreover,Tg and thermal stability of M-PI and E-PI were increased effectively.