An efficient graft modification strategy was developed based on photo-induced organocatalyzed atom transfer radical polymerization (O-ATRP) for the functionalization of poly(vinylidene fluoride) (PVDF) based copolymer. P-anisaldehyde was served as an organic photoredox catalyst to mediated O-ATRP of methyl methacrylate (MMA) and glycidyl methacrylate (GMA) in the presence of poly(vinylidene fluoride-co-chlorotrifluoroethylene) (P(VDF-co-CTFE)) as the macroinitiator under UV irradiation. Excellent temporal control and low catalyst concentration was achieved. Chain extension confirmed the chlorine atom attached to the graft polymer chain end. Metal-free P(VDF-co-CTFE)-g-PMMA and P(VDF-co-CTFE)-g-PGMA with varied graft contents were obtained, which would find potential applications in dielectric materials.