Abstract: Provided are a method of manufacturing a cathode active material for a lithium battery, and a cathode active material obtained by the method. The method includes forming a precursor of a one-dimensional nanocluster manganese dioxide with a chestnut-type morphology, inserting lithium into the formed precursor and synthesizing a one-dimensional nanocluster cathode active material particle with a chestnut morphology, coating a water-soluble polymer on a surface of the cathode active material particle, adsorbing a metal ion to the surface of the cathode active material particle coated with the water-soluble polymer, and sintering the cathode active material particle to obtain the one-dimensional nanocluster cathode active material with a chestnut morphology.