Abstract: Three compatibilizers,SEBS，poly(propylene-graft-styrene)(PP-g-PS), and Surlyn were emploved and compared in the blends of polypropylene/polystyrene. SEBS resulted in a great increase of impact strength,but a decrease in tensile strength. PP-g-PS also improved the compatibility and reduced the coalescence of the dispersed partides and the average particle size. In confrast. Surlvn resulted in moderate decrease of mechanical properties， no improvement in the compatibility was observed

Key words: polypropylene;polystyrene, compatibilizer, morphology;mechanical property