The present invention relates to an olefin-based polymer, which has (1) a density (d) ranging from 0.850 to 0.865 g/cc, (2) a melt index (MI, 190° C., 2.16 kg load conditions) ranging from 0.1 g/10 min to 3.0 g/10 min, and (3) a soluble fraction (SF) of 10 wt % or more at −20° C. in cross-fractionation chromatography (CFC), in which a weight average molecular weight (Mw) of the soluble fraction is in a range of 50,000 g/mol to 500,000 g/mol. The olefin-based polymer according to the present invention exhibits improved anti-blocking properties as a low-density olefin-based polymer.