The layer-multiplying coextrusion has been recognized as one of efficient and controllable ways to achieve alternating multilayer structure consisting of two different polymeric layers. Studies have found that the distinct structure is capable of endowing the final products with unique performances. However, the issues induced from the poor adhesion between layer interfaces and the overloading of functional particles commonly may not meet the requirement of the mechanical balance between strength and toughness. In the current work, a kind of shell-mimicking polypropylene (PP) was fabricated by coextruding two types of isotactic PP with different molecular weights. The morphological observation exhibited that β-cylindrites were formed in the low-molecular-weight layers and highly orientated lamellae appeared in the high-molecular-weight layers. Both of DSC and WAXD results further revealed that the content of β-cylindrites was gradually increased accompanied with the multiplication of layer numbers due to the difference of relaxation time between adjacent layers and the enrichment of layer interfaces. The results of tensile tests display that the tensile strength and elongation at break were distinctly enhanced from 35MPa and 730% to 50MPa and 870%, when the layer numbers were increased from 2 to 32. Accordingly, it is believed that the shell-like structure with alternating toughening and strengthening layers tailored through the layer-multiplying process shows a great potential in fabricating superior PP products with optimal mechanical balance.