High density polyethylene (HDPE) and polypropylene (PP) containing different content of EPR (0%, 18%, 21%) are selected to fabricate toughness materials through high speed thin wall injection molding (HSTWIM). The influence of shear action and confinement on the phase morphology, crystallization behavior and mechiancal behavior is studied with the comparison of two preparation methods-HSWIM and compression molding (CM). Alternating multilayer structure is observed in all HSTWIM samples, and this methods is thought to be a useful method of morphological control for various functional materials[1, 2, 3]. Such multi-layered structure provides a confinment for the orientation of molecular chains and polymer crystals, and the interface between PP and PE is benefit to the epitaxial growth of PE crystals onto PP. In addition, thanks to the “phase in phase” phenomena in ICP[4], EPR will migrate from PP phase to PE phase during processing. Some EPR distributed on the interface of layers in multilayer structure is observed, it should be owing to the fast cooling rate of HSTWIM. Multi-layered structure, epitaxial crystallization and EPR in interphased should be response for the enhanced toughness of HSTWIN specimens than that of CM specimens. The influence of composition ratio on phase morphology and mechanical structure also investigated. We hope our study could provide some guidance for the manufacture of high perforsmance materials and functional materials.