In this work, we successfully developed a novel wet chemical method to prepare LiNi0.5Mn1.5O4 coated LiMn2O4 (LMO@LNMO), in which commercial LiMn2O4 produced by solid state reaction method was used as the starting material and a nitrate precursor containing Li, Ni and Mn was used to form LiNi0.5Mn1.5O4 coating layer. There is no precipitant, chelating agent and washing process needed. The effect of the calcination temperature and the mass ratio of LiMn2O4 and LiNi0.5Mn1.5O4 (mLMO:mLNMO) were systematically studied. LMO@LNMO was investigated by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS), which showed that a completed coating layer was formed via the wet chemical method and some Ni2+ in LiNi0.5Mn1.5O4 were diffused to LiMn2O4 to form a Ni concentration-gradient structure after calcination. Typically, LMO@LNMO with the calcination temperature of 800°C and the mass ratio of 9:1 (mLMO:mLNMO) showed an initial discharge specific capacity of ∼100 mAh·g−1 between 3.0 and 4.3V vs. Li+/Li at 55°C, and greatly improved cyclic performance with a capacity retention of 81.9% over 400 cycles. The thermal safety of LMO@LNMO was also enhanced according to the differential scanning calorimetry (DSC) results.