The invention discloses a millimeter-wave circularly-polarized array antenna and a radiation body thereof. The antenna comprises a first dielectric substrate, a second dielectric substrate, a first floor, a feeding network and the radiation body, wherein the radiation body, the first dielectric substrate, the first floor, the second dielectric substrate and the feeding network are sequentially arranged from top to bottom, the radiation body comprises a radiation plate and a plurality of radiation units, the plurality of radiation units are arranged on the radiation plate, each radiation unit comprises four short-circuit patches, L-shaped branches are loaded at opposite corners of two of the short-circuit patches, cutting parts are arranged at opposite corners of the other short-circuit patches, and each radiation unit is connected with the first floor via a through hole in the first dielectric substrate. The millimeter-wave circularly-polarized array antenna has relatively long bandwidth, relatively large gain and relatively wide circularly-polarized shaft ratio and is simple in structure, and the requirement (42.3-48.4GHz) of a broadband wireless access system of industry and information technology planning used in millimeter-wave band mobile service can be met.