The self-supported ZnO nanorods (ZnO NRs) @ reduced graphene oxide (rGO) composites were synthesized by a simple one-step hydrothermal method, and ZnO@rGO/polyvinylidene difluoride(PVDF) flexible composite film piezoelectric nanogenerators were prepared by spin-coating method. The studying results show that the output performance of the ZnO@rGO/PVDF flexible composite film piezoelectric nanogenerator increases first and then decreases with the ZnO@rGO doping mass. When the mass fraction of ZnO@rGO is 3.0 %, the output voltage and current of the ZnO/PVDF nanogenerator can reach 9.06 V and 0.74 μA, which are 120 % and 124 % higher than those of the ZnO/PVDF nanogenerator only doped with 3.0 %ZnO NRs, respectively. When the load resistance is 10 MΩ, the maximum output power of ZnO@rGO/PVDF flexible composite film piezoelectric nanogenerator is 5.79 μW. After 4 000 cycles of testing, the output performance of the prepared ZnO@rGO/PVDF flexible composite film piezoelectric nanogenerator is stable. The nanogenerator can monitor the walking and running posture of the human body and record the numbers of exercises. It is expected to be implanted into wearable electronic devices and used as self-powered pressure sensors.