Ground calcium carbonate (GCC) is usually of smooth/flat surface and pointed edges angles which have disadvantageous effects on the mechanical properties of composite polymer materials filled with the powder. Nanometer calcium carbonate reactants would deposit, nucleate and grow on surface of ground calcium carbonate with micron grain size by adjusting suitable technical parameters in Ca(OH)2–H2O–CO2 system. Compared with the uncoated powder, composite ground calcium carbonate (CGCC) is of rough surface, blunt edges, larger specific surface area, larger in whiteness. In this paper, we reported the successful preparation of CGCC particles, and found GCC/Ca(OH)2 weight ratio was the key parameter. Some technological parameters were mainly analyzed for the coating process. Furthermore, We also prepared nanosized calcium carbonate coating GCC at higher temperature (40 °C) using additives. Filling tests showed that a rough surface of the CGCC enhanced contact opportunities and improved the interface between polymer and CGCC blended with polypropylene (PP).