Recently, lithium titanium oxide material has gained renewed interest in electrodes for lithium ion rechargeable batteries. We investigated the influence of excess Li on the structural characteristics of lithium titanium oxide synthesized by the conventional powder calcination method, considering the potential for mass production. The lithium excess ratio is controlled by using different weight of Li2CO3 powder during calcination. X-ray diffraction (XRD) measurement for the synthesized powder showed that the lithium titanium oxide material with excess lithium content had a spinel crystal structure as well as a different crystal one. In addition, high resolution transmission electron microscopy (HRTEM) and field emission scanning electron microscopy (FESEM) measurement revealed that the lithium titanium oxide powders with a lithium excess ratio of 5-20% exhibited a two phase formation. Inductively coupled plasma - atomic emission spectrometer (ICP-AES) and energy dispersive x-ray spectroscopy (EDX) measurements were used to analyze composition of the lithium titanium oxide powder. These results suggested that the conventional calcination method, considering the potential for mass production, formed two phases according to the Li excess amount in initial raw materials.