Epoxy-functionalized ethylene-octene copolymer (POE-g-PGMA) was prepared by ⁶⁰Co γ-ray radiation, and polyamide 6/polyethylene-octene blend (PA6/POE) containing POE-g-PGMA was prepared by twin-screw melt extrusion. In this study, the mechanical properties, thermal properties, surface morphology, interfacial compatibility, and water absorption properties of PA6/POE blends with added POE-g-PGMA were investigated. The results showed that GMA was successfully grafted on POE by γ-ray radiation. The morphological analysis showed that the addition of POE-g-PGMA enhanced the dispersion of POE particles in the PA6 matrix. In particular, it demonstrated that with the addition of POE-g-PGMA, pure PA6 has good interfacial compatibility with POE. The results of the Molau test confirmed the compatibilization reactions between POE-g-PGMA and PA6. The thermal analysis showed that the addition of POE and POE-g-PGMA in the dispersed phase had negligible effect on the melting behavior of PA6; however, the crystallization temperature of PA6 improved by approximately 18 °C during the cooling crystallization process, and the crystallinity increased by approximately 4.5%. Furthermore, the impact strength of the compatibilized PA6/POE blend was significantly higher than that of the PA6/POE blend, with the highest value of impact strength obtained at a POE-g-PGMA content of 3% being approximately 2.75 times greater than that of pure PA6 under the experimental conditions.