Abstract: High-density polyethylene (PE-HD)/aluminum oxide (Al2O3) composites were prepared by melt blending with sodium ionomer (EMAA-Na) as a compatibilizer. The cross-section structure of the composites was observed by scanning electron microscopy, and steady and dynamic rheological properties were investigated by a plate rheometer and capillary rheometer. The results indicated that the interfacial adhesion between PE-HD and Al2O3 was improved with the addition of EMAA-Na, leading to disappearance of the gap between the matrix and fillers. The steady-shear viscosity and elongational viscosity were improved with increasing the content of EMAA-Na, and PE-HD/Al2O3/EMAA-Na composites showed a shear-thinning and strain-hardening behavior. Dynamic rheology measurement indicated that the incorporation of EMAA-Na improved the interaction between different components, thus enhancing the elasticity of composite.