The invention belongs to the technical field of lithium-ion power batteries, and in particular relates to a mixed positive material of a high-capacity lithium-ion power battery. The mixed positive material comprises lithium iron phosphate A and a lithium nickel cobalt manganese ternary active substance B, wherein the surface of the A is coated with a polypyrrole layer; the median particle size of the A is smaller than or equal to 15 microns; the sizes of single-crystal particles of the B are greater than or equal to 1.0 microns; the surface of the B is coated with a metal fluoride layer. Compared with the prior art, the disadvantage of low compaction density caused by a ternary material is effectively overcome by reasonably optimizing the sizes of the single-crystal particles of the ternary material and the median particle size of the lithium iron phosphate, so that the mixed positive material has high compaction density; the surface of the lithium iron phosphate is coated with the polypyrrole layer and the surface of the ternary material is coated with the metal fluoride layer, so that the safety performance, the rate performance, the high-temperature cycling performance, the low-temperature performance and the safety performance of the lithium-ion power battery with the mixed positive material can be improved.