Lithium secondary battery positive active material powder, manufacturing method thereof and lithium secondary battery

The invention provides a lithium secondary battery positive active material powder which contains lithium nickel manganese oxide cobalt composite capable of raising the capacity of a unit volume and a capacity maintaining rate of a lithium secondary battery, a manufacturing method thereof and a lithium secondary battery which has good battery performances on the capacity of a unit volume and a capacity maintaining rate. The lithium secondary battery positive active material powder is characterized by comprising secondary granules formed by coagulated by primary granules of lithium nickel manganese oxide cobalt composites represented by the following general formula (1): LixNi1-y-ZmnyCozO2, wherein (1) an average granule diameter of the secondary granules of the secondary battery positive active material powder is 4 [mu]m- 30[mu]m, and the pressure density of the lithium secondary battery positive active material powder being compressed is above 3 ton/cm2 is 3.55 g/cm3.