PVDF-TrFE-based wearable nanogenerators were designed and fabricated with enhanced performances via reduced graphene oxides (rGO) and in situ electric polarization. Our laboratory-made polarization system may complete the in situ poling of PVDF-TrFE films in 5min without heating, which has the advantages of high production efficiency, excellent piezoelectric performances, and favorable uniformity, compared to traditional poling approaches. The addition of rGO into PVDF-TrFE significantly improved the crystallinity of the -phase PVDF-TrFE and enhanced the formation of hydrogen bonds via interaction of dipoles between rGO and PVDF-TrFE. This further improved the energy-harvesting performances of these piezoelectric nanogenerators with 1.6 times of the open-circuit voltage and 2 times of the power density than that of pure PVDF-TrFE-based devices. The high production efficiency and excellent piezoelectric performances of in situ polarized rGO/PVDF-TrFE make them of great potential for self-powered, wearable/portable devices.