Polypropylene (PP), as one of the three universal plastics, has been widely used in fields such as medical, automotive, and packaging, etc. The article reviewed the research progress of in-situ microfibrillar technology in PP foaming material, conductive material, and reinforcing and toughing PP in recent years. The results showed that by forming in-situ microfibrils in PP, the melt strength of PP can be improved, the merging of bubbles during the foaming process was reduced, the size of bubbles decreased and the density of bubbles increased, the foaming performance of PP was improved. By forming a conductive microfibrillar network structure in PP, the percolation threshold of PP composites can be effectively reduced. The in-situ formation of microfibrils can significantly improve the crystallization ability of PP, and some polymer microfibrils can induce the formation of shish kebab structure in PP, achieving reinforcement and toughening of PP, meawhile, under the synergistic effect of compatibilizers, its reinforcement and toughening effect on PP was more obvious.