An elastomer/rigid particle filler with core-shell structure was prepared by twin-screw extruder according to an encapulation model. It was used to toughen and reinforce polypropylene (PP). An original idea of a one-step processing method was adopted in creating PP/polyoctene- ethylene/talc ternary composites. The rheological behavior of PP was changed and the mechanical properties were improved. SEM observation showed that the core-shell structured filler dispersed better in copolypropylene than in homopolypropylene. Two reasons were proposed and proved by the rheology test and SEM observation.