Abstract:In the present study, the structural properties which included the X-rays diffraction, and DSC, the mechanical properties, which include tensile test, threepoint bending test (Bending Test), hardness test and thermal conductivity of the polymers reinforced with calcite (PVC/CaCO 3 ) at different temperature (25-40-80-120-160-200-220) °C. The research results showed that the X C degree of X-ray diffraction decreased at high temperatures (220 ˚C), while the inter-polymerized polymer (PVC / CaCO 3 ) increased at high temperatures. The DSC test results showed that the degree of crystallinity (X C ) decreases at high temperatures (220 ˚C). The mechanical test results, their values were found to decrease at (220 ˚C) higher temperatures. Finally, the obtained results were indicated that the thermal conductivity values decrease at (220 ˚C). Keywords IntroductionPolyvinyl chloride PVC is one of the most commonly used man-made polymers because of the unrivalled combination of properties that it offers. It is the ratio of economic cost to performance makes it immediately more accessible than most other materials and the diversity of ways in which it