Since the use of olivine-structured lithium iron phosphate (LiFePO₄, LFP) as a cathode material for rechargeable lithium batteries was first reported by Goodenough and co-workers in 1997, LFP has been extensively and intensively studied, owing to its significant advantages including high theoretical capacity (170 mAhg^-1), long cycle life(≥2000), acceptable operating voltage (3.4V vs. Li⁺/Li), environmental benignity, high safety, and low cost. Unfortunately, LFP possesses a major drawback in its sluggish kinetics of electron and lithium-ion transport, which restricts its rate performance. To date, many studies have been made to reduce the particle size and incorporate carbon additives of LFP,  so as to improve the electronic conductivity and thus enhance the diffusion of Li ions across the LFP/FePO₄ interface. Many techniques have been developed to synthesize nanosized LFP with uniform size distributions, which include the hydrothermal method, polyol and solvothermal methods, sol‑gel  methods,  reverse  micelle  process and spray pyrolysis. Among them, the polyol method is considered one of the most facile and efficient methods to synthesize nanosize LFP with high crystallinity. Therefore, in this study, we would like to control the size, crystallization degree, morphology of LFP particles via a facile, low temperature polyol method to improve its ionic and electric transport properties. In this method, the polyol solvent (ethylene glycol) could generate a reductive atmosphere even in the absence of any reductive agent. Highly-dispersed LFP cathode nanospheres with olive-shape was synthesized by a simple polyol refluxing process without any post heat treatments. As-obtained samples were characterized by XRD, FE-SEM, TEM, BET etc. As confirmed by these characterization results that olive‑like LFP nanoparticles with high crystallization degree were successfully prepared in this study. And the sizes of these nano/micro-particles are ranged from 50 nm to 800 nm. The various processing parameters, namely, reaction temperature and material ratio, have been varied, and the effects on the growth of LFP particles have been analyzed systematically to optimize the preparation condition. Finally, the electrochemical properties especially the rate performance of as-resulted LFP nanoparticles, employing the reported as comparison,  were discussed, which is the key point of their application in Li ion batteries.