<p>OF THE DISCLOSURE The present description relates to an olefin block copolymer with enhanced processability as well as excellences in elasticity and heat resistance, and a preparation method for the same. The olefin block copolymer includes5 first and second segments, each containing an ethylene or propylene repeating unit and an a-olefin repeating unit at different mole fractions, where the second segment is dispersed in the form of a closed curve as a dispersed phase on the first segment according to a TEM (Transmission Electron Microscope) image.</p>
