Polycarbonate (pc)/polypropylene (pp)/silicate attapulgite (AT) ternary nanocomposites were first prepared via the two-step melt blending process. Phase structure of the ternary composites was characterized by transmission electron microscopy (TEM) and dynamic mechanical analysis (DMA), in which the morphology of encapsulation of AT by PP in the PC matrix were observed. The mechanical properties of the ternary composites were investigated using the tensile tester and lzod impact tester. The results show that encapsulation of AT by PP in PC enhances the toughness of the matrix effectively and give the best tensile and impact strength.