The present disclosure provides a lithium manganate positive electrode active material, comprising a lithium manganate matrix and a cladding layer, where the cladding layer comprises an organic bonding material, one or more A-type salts, and one or more B-type salts. The lithium manganate positive electrode active material of the present disclosure significantly reduces the content of transition metal manganese ions within a battery through combined action of the organic bonding material, the A-type salts, and the B-type salts, thereby slowing down the decomposition and consumption of the SEI film (solid electrolyte interphase) by transition metal manganese, and improving the capacity retention rate and impedance performance of the battery.