Polycarbonate (PC)/cerium (IV) oxide (CeO2) composites are prepared by a melt-compounding method using a twin-screw extruder. The effect of the CeO2 content on the damping property of the composites was investigated using scanning electron microscopy, dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA). In addition, the composites' mechanical properties were studied through tensile and impact tests. The DMA results revealed that the addition of CeO2 (0.5 wt%) improved the damping property of the composite. TGA showed that the thermal stability was improved when the CeO2 became 1 wt%. Mechanical tests revealed that both the tensile and impact strengths were substantially improved when 1 wt% CeO2 was added . Finally, it can be concluded that the 0.5 wt% CeO2-filled PC composite can be used as a structural damping material.