LiFePO4/C composites were synthesized by a novel carbothermal reduction method based on the low-temperature solution reaction between LiNO3-Fe (NO3)3-NH4H2PO4-sucrose. The sucrose amount, sintering temperature, sintering time, and heating temperature for synthesis of LiFePO4/C cathode was optimized. The materials were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) and charge–discharge tests. The results showed that sintering temperature and sucrose amount have more significant effects on discharge capacity than drying temperature and sintering time. Optimum LiFePO4/C was prepared by sintering the precursor obtained by heating at 60 with a sucrose amount of 5.0g at 800.0 for 12 h. Being charged–discharged at 0.5C between 2.5 and 4.2 V, the LiFePO4/C synthesized at the optimum conditions shows good electrochemical performances with an initial discharge capacity of 138.7 mAh·g−1 and a capacity retention ratio of 98.6% after 50 cycles.