Layered LiCo1/3Ni1/3Mn1/3O2 was synthesized by a newly developed water-in-oil emulsion method. The synthesis process of LiCo1/3Ni1/3Mn1/3O2 was investigated by TG/DTA, FTIR and XRD. Li2CO3, NiO, CoO and Mn2O3 are the intermediate products. With the calcination temperature increasing, Li2CO3 undergoes direct reactions with NiO, CoO and Mn2O3 to form LiCo1/3Ni1/3Mn1/3O2. The kinetics of formation of LiCo1/3Ni1/3Mn1/3O2 by the water-in-oil emulsion method is faster than the case of the conventional solid-state reaction between lithium carbonate and corresponding reactants. The single phase of LiCo1/3Ni1/3Mn1/3O2 was obtained at 650℃. Itwas found that the submicro-sized LiCo1/3Ni1/3Mn1/3O2 synthesized at 850℃ for 4h in oxygen atmosphere presents the best electrochemical performance, which delivers an initial discharge capacity of 157mAh g-1 in the cut-off voltage of 2.7-4.2V, and exhibits good cycle performance.