Abstract: SEBS/PPO blends were prepared with a twin-screw extruder, and the morphology was studied by atomic force microscope（AFM）and its mechanical properties were compared. With increasing PPO content light spot increased and the PPO and PS phase were completely miscible. When the ratio of SEBS and PPO was 80/20, EB segment was continuous phase and PS segments and PPO were dispersed phase. The hard segment structure was from dispersed phase to two continuous phase and then to continuous phase（SEBS/EB=20/80）.The tensile strength of the SEBS/PPO blends increased sharply and the elongation at break decreased with increasing PPO. Both tensile strength and elongation at break declined with increasing oil amount.

Key words: poly（2, 6-dimethyl-1, 4-phenylene oxide）, morphology, mechanical property, rheology