We carried out tensile impact test and very low speed tensile test on ethylene-based Ionomers (E/15wt %MAA) to clarify the relation between impact toughness and high-ordered structure. We also studied the changes in high-ordered structure under deformation by observing Differential Scanning Calorimetory (DSC) and Small-Angle X-ray Scattering (SAXS) of fractured surface. Na Ionomers showed ductile fracture in both high speed tensile impact (3 m/s) and very low speed tensile (2 mm/min). The disappearance of secondary melting point (Ti) in Na Ionomers was due to the destruction of ordered structure surrounding the ionic aggregate. Similar behavior was observed in 60% (or less) neutralized Zn Ionomers. However, 80%: neutralized Zn Ionomer showed brittle failure in high-speed tensile impact, and Ti did not disappear. SAXS studies of Na and Zn Ionomers after fracture, show no change both after molding (no aging) and after aging.