A multi-band antenna package structure includes a first redistribution layer; an integrated circuit layer, formed on the first redistribution layer, comprising at least one metal via, at least one metal pillar, an integrated circuit chip, and a molding layer, wherein the molding layer is used to fill openings formed by the metal via, the metal pillar and the integrated circuit chip which are disposed on the first redistribution layer, the metal via is electrically connected to one of the first metal patterns of the first redistribution layer; a second redistribution layer, formed on the integrated circuit layer; and a first antenna unit layer, comprising a first dielectric layer and third metal patterns formed in openings of the first dielectric layer, wherein at least one of the third metal patterns is electrically connected to one of the second metal patterns, and the third metal patterns form a first antenna unit.