The present disclosure relates to a cathode active material, and more particularly, to a cathode active material doped with a trivalent metal (Me) and a lithium secondary battery comprising the same. According to one aspect, there is provided the cathode active material doped with the trivalent metal (Me), represented by the formula LixMn2MeyO4 (here, x is from 0.5 to 1.3, and y is from 0.01 to 0.1). According to the present disclosure, release of manganese ions of the cathode active material greatly reduces, and consequently, capacity and cycle life of the battery may be significantly improved.