Spinel LiMn2O4 powders have been successfully synthesized by a hydrothermal method directly, which is no any pretreatment and following treatment in the process. The structure and morphology of the powders were studied in detail by means of X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and thermogravimetric analysis (TGA). The data reveal that the products have well-defined stable spinel structure, and the particles show distinctive crystal faces with 50–300nm in particle sizes. The electrochemical characteristics of the spinel materials are measured in the coin-type cells in a potential range of 3.2–4.35V versus Li/Li+. The as-synthesized LiMn2O4 delivers reversible capacity of about 121mAhg−1 at a current density of 1/10C. Cycled the cell to 40 cycles, the capacity remains at about 111mAhg−1 at 1/2C.