The polypropylene(PP) composites filled with nano-calcium carbonate(nano-CaCO_3) were prepared by the method of melt blending process and and subsequently molded into impact specimens by injection molding,the impact strength(σ_Ⅳ) and the fracture of the PP/CaCO_3nanocomposites were obtained by the impact test,and the fractography of the PP/CaCO_3nanocomposites were observed by Scanning Electron Microscope(SEM),the contour curve of the fractography of the PP/CaCO_3 nanocomposites was extracted by the image p...