An electrode active material for a lithium secondary battery, a method of preparing the electrode active material, an electrode for a lithium secondary battery which includes the same, a lithium secondary battery using the electrode. The electrode active material includes a core active material and a coating layer including magnesium aluminum oxide (MgAlO2) and formed on the core active material. 1s binding energy peaks of oxygen (O) in the electrode active material measured by x-ray photoelectron spectroscopy (XPS) are shown at positions corresponding to 529.4±0.5 eV, about 530.7 eV, and 531.9±0.5 eV, and a peak intensity at the position corresponding to 529.4±0.5 eV is stronger than a peak intensity at the position corresponding to about 530.7 eV.