A novel approach to functionalize polypropylene (PP) is presented. This method consists of two steps. Firstly, oligomers of glycidyl methacrylate (GMA) were synthesized via UV photo-polymerization using benzophenone (BP) as initiator. Secondly, the GMA oligomers were grafted onto PP, which was initiated by the free radicals generated through the reactivation of semipinacol dormant groups in the oligomers. By this method, the functionalization of PP could be facilely achieved in a simple system without either organic peroxide initiator or monomer; additionally, degradation of the substrate PP was not observed. This presentation is mainly focused on the characterization of the grafted PP products by XRD, DSC and TGA measurements. It is demonstrated that the melting temperature, crystallinity and the initial decomposition temperature of the grafted PP were all increased, compared with those of the origin PP; the functionalization of PP led to the change of the crystal form from the mixed form of α and β into only α form.