Abstract: A novel strategy for preparing maleic anhydride-grafted polypropylene (PP-g-MAH) with high crystallinity and high grafting ratio was proposed. Using chlorinated polypropylene (CPP) with high crystallinity and low chlorination degree as the starting material, the reactive carbon-chlorine bonds were exploited to graft toluene onto the polypropylene backbone via the classic Friedel-Crafts reaction, yielding arylated polypropylene. Leveraging the facile formation of benzylic radicals, the copolymerization of maleic anhydride (MAH) and styrene (St) was subsequently initiated under mild conditions, successfully affording modified PP-g-MAH with a maximum MAH grafting ratio of up to 10.5%, a high melting point (152.4 ℃) and a high crystallinity (30.67%). This approach effectively addresses the issues of low grafting efficiency and compromised chain regularity associated with conventional melt-grafting methods, thereby paving the way for high-performance applications of polypropylene.