The work aims to reveal the effect of the addition of fibrous fillers and radiation crosslinking on the crys-tallization of polylactic acid, in order to provide certain reference for the theoretical research and production of high polymer material with irradiation technology. The effect of different γ-ray irradiation doses on the crystallization behavior and crystallization properties of polylactic acid/flax composites was investigated with triallylurethanylcyanate (TAIC) as a cross-linking agent. Spherulites (diameter≈100 μm) were formed in the unirradiated composites, and the surface of the fibers had obvious transverse crystal phenomenon. With the increase of irradiation dose, the diameter of spherulite was reduced below 50 μm, while the transverse crystal phenomenon was not obvious. Spheroidal and transverse crystal phe-nomena could not be observed in composites after irradiation with high dose gamma rays. DSC results showed that, as the irradiation dose increased, the glass transition temperature and cold crystallization temperature increased gradually, and the melting point and crystallinity gradually decreased. Irradiation cross-linking mainly occurred in the amorphous region, and the radiation degradation caused the edge of the crystal region to be damaged, and partial crystal region transformed into amorphous region. The WAXD results showed that, the irradiation modification did not change the crystal form of the PLA, but only lowered the crystallinity of composites. Fibers induce transverse crystals of polylactic acid, while the irradiation cross-linking hinders the formation of polylactic acid crystals, and as the irradiation dose increases, the hindrance effect increases. The irradiation crosslinking does not change the crystal form of polylactic acid. The influence of irradiation technology on the aggregate structure of polylactic acid composites is mainly discussed, and certain reference value is provided for the theoretical research and production of high polymer material with irradiation technology.