A process to produce a positive electrode active material for a lithium secondary battery, having a large volume capacity density and high safety, uniform coating properties, charge and discharge cyclic durability and low temperature characteristics even at a high charge voltage is disclosed.The positive electrode active material is a lithium-containing composite oxide represented by the formula Li.sub.pN.sub.xM.sub.yO.sub.zF.sub.a, wherein N is at least one element selected from the group consisting of Co, Mn and Ni, M is at least one element selected from the group consisting of Sn, Zn, Al, alkaline earth metal elements, and transition metal elements other than the N element, O.9.ltoreq.p.ltoreq.l.1, 0.97.ltoreq.x.ltoreq.l.00, 0.ltoreq.y.ltoreq.0.03, 1.9.ltoreq.z.ltoreq.2.1, x+y=1 and 0.ltoreq.a.ltoreq.0.02. The N element source powder having an average particle size of from 2 to 20 .mu.m, is impregnated with the M element salt aqueous solution, and the prepared dry powder comprising the N element, M element, a lithium source and optionally a fluorine source is fired at from 700 to 1 ,050.degree. C. in an oxygen-containing atmosphere.