Calcium carbonate@methyl methacrylate-polyvinyl chloride (CaCO3\@PMMA-PVC) nanocomposites with outstanding mechanical performance have been successfully prepared. Precise control over the CaCO3 surface modification -via a green, facile, and reproducible seed dispersion polymerization, not only efficiently avoids agglomeration of the incorporated nanofillers, but also enStres enhanced interfacial adhesion between components, endowing the resultant composite with high performance. Specifically, the maximum tensile strength of PVC composites was achieved when the addition of CacCO(3)@PMMA NPs is 4 Wt %, and the grafting content is 25%. Compared to pure PVC (P-PVC), the composite shows robust mechanical properties with a 116.7% increase in modulus and a 57.0% improvement in hardness.