The high impact polypropylene (hiPP) with excellent impact resistance has become a representative product of PP in industry. Study on the relationship between structure and property is always the one of the focuses in this field. The latest research progress of structure-property correlation in recent years is reviewed. Based on the analysis on morphology

the dispersed phase distribution to achieve high impact resistance has been presented. More generally at microscopic structure

the compositions of hiPP are classified as ethylene-propylene rubber

ethylene-propylene segmented copolymer

ethylene-propylene block copolymer and isotactic polypropylene

and their respective role has been described as well as effect factors.