Abstract: Highdensity polyethylene (HDPE) and polyamide-6 (PA-6) blends were prepared by melting 80∶20 blends and samples of the blends were irradiated in air with γ-ray. Effects of γ-ray irradiation on the structure and properties of the blends were investigated. On the basis of morphologies obtained by the scanning electron microscope (SEM), mechanical properties and absorption ratio test results, it has been shown that the phase structure of the blend that has undergone γ-ray irradiation is different from the un-irradiated blend, and there are positive changes in the barrier properties, tensile strength and elongation at break, but the impact strength is decreased while the blend has been irradiated for 4h (absorbed dose is 15.84kGy). In all samples, the one that has been irradiated in air with γ-ray for 4h has the lowest absorption ratio of xylene, while the one undergone 7h irradiating process (absorbed dose is 27.72kGy) has the best mechanical properties. As the structure of the blend gradually destroyed with increasing the irradiation dose to the blend, the mechanical properties decreased apparently.