Nanometer-sized LiFePO₄ with a well-developed olivine-type structure was synthesized in the dimethyl sulfoxide (DMSO)/H₂O system under ambient pressure and 108 ℃. From IR analysis, less amount of Fe^3＋ ions were proved to exist in the composite by solution-phased method. The sphere-like LiFePO₄/C nanocomposite was obtained by sintering the mixture of nanometer-sized LiFePO₄ and glucose at 600 ℃ under inert atmosphere for 3 h. The electrochemical tests showed the specific capacity of LiFePO₄/C nanocomposites at discharge rates of 0.2 C was 157.2 mAh/g. A capacity of 126.1 mAh/g at 5 C and 103.4 mAh/g at 10 C was even achievable, with no significant capacity fading after 200 cycles.