In this study, dynamic vulcanization process was used to improve the thermal properties of calcium carbonate filled composites. The composites were prepared using a Z-blade mixer at 180°C and rotor speed 50rpm. Thermogravimetric analysis (TGA) and Differential scanning calorimetry (DSC) techniques were used to analyze the thermal properties of the composites. The vulcanized and unvulcanized PP/EPDM composites were filled by CaCO3 at 0, 10, 20, 30, and 40 %wt. Meanwhile, thermogravimetric analysis indicates that the total weight loss of PP/EPDM/CaCO3 composites decreased with increasing filler loading. Dynamic vulcanized composites have higher thermal stability, while the crystallinity of PP/EPDM/CaCO3 composites were increased as compared to unvulcanized composites. Therefore, the thermal properties were improved by the presence of dynamic vulcanization process.