A two-step hydrothermal approach is employed to synthesize LiMn2O4/carbon nanotube (LMO/CNT) composite powders. X-ray diffraction, scanning electron microscopy, thermal gravimetry and N2-adsorption/desorption are used to characterize their structures and compositions. Galvanostatic cycling in coin-cells is adopted to measure their electrochemical properties as cathode materials of lithium-ion batteries. A LiMn2O4 pure phase of high crystallinity is observed with CNT homogeneously dispersed in the composite network. The electrochemical properties of them are associated with two factors, i.e. the content of CNT in the hydrothermal process and the annealing temperature at the subsequent heat treatment step. Excellent rate capability of these LMO/CNT electrodes can be achieved.