Deformation behavior of polyethylene/modified montmorillonites with polymerizable surfactant (PE/P-MMT) nanocomposite with strong interfacial interaction was studied by means of morphology observation and X-ray scattering measurements. The orientation of PE chains was accompanied by the orientation of well-dispersed MMT platelets due to the presence of strong interfacial interaction, and both of the orientations were parallel to the deformation direction. The high degree of orientation of MMT platelets and PE chains resulted from the synergistic movement of PE matrix and MMTs, which originated from the presence of a network-like structure. Meanwhile, the. existence of MMT platelets with good mobility during deformation and strong interfacial interaction with PE matrix could further improve the break energy of material by restraining the initiation and growth of cavities during deformation. In contrast, PE/MMT nanocomposite with no strong interfacial interaction and poor dispersed state of MMT sheets showed the weaker orientation of both PE chains and MMT platelets, and a strong cavitation during deformation.