F-doped LiFePO4/C nanoparticles were synthesized via a low-temperature hydrothermal reaction followed by high-temperature treatment. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectrometer, X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and transmission electron microscope (TEM). To investigate their electrochemical properties, the cyclic voltammetry, electrochemical impedance spectroscopy curves, charge–discharge curves and cycle life test were carried out. The results show that F-doping can modify the microstructure and further improve the electrochemical performance of these cathode materials. These F-doped LiFePO4/C nanoparticles show obviously better high rate performance and stable cycle ability.