A series of composites of PPO/PA 6 with improved toughness were synthesized by using epsilon-caprolactam as a reactive solvent. Inserting minor PPO macromolecules (1-3 wt %) into PA 6 matrix obviously reduced the crystallinity of PA6. Two crystallization temperatures were found when 6 wt % PPO was added. SEM revealed that the phase morphology of the composites could be manipulated by varying the content of PPO in PA 6. As a consequence, the impact strength and the elongation of PPO/PA6 were improved with maintenance of tensile strength when quite small content of PPO (1-3 wt %) was incorporated.