Polyolefin having density, measured according to ASTM D1505, of 0.910 g/cm 3 to 0.930 g/cm 3; melting point, determined by DSC as set out in the specification, of 120 to 124°C; SCBs(Short Chain Branch), determined by 1 H NMR, per 1000 carbons of 1.0 to 5.0; and block comonomer distribution index(BCDI) calculated by the following Formula 1 of 1.0 or less: BCDI = ASL fi < 8 nm + ASL fi > 30 nm ASL fi 8 ∼ 30 nm in the Formula 1, ASL fi(<8nm) is the fraction(%) of chains having ASL (Average Ethylene Sequence Length) less than 8nm, by SSA (Successive Self-nucleation and Annealing) analysis, ASL fi(>30nm) is the fraction(%) of chains having ASL greater than 30nm, by SSA analysis, and ASL fi(8~30nm) is the fraction(%) of chains having ASL of 8 to 30nm, by SSA analysis; wherein the SSA is conducted using differential scanning calorimeter, by heating the polyolefin to the first heating temperature of 120 to 124°C, maintaining for 15 to 30 minutes, and then, cooling to 28 to 32°C, and while decreasing heating temperature by stages with (n+1)th heating temperature being 3 to 7°C lower than nth heating temperature, repeating heating-annealing-quenching until the final heating temperature becomes 50 to 54°C, and finally, raising the temperature from 30°C to 160°C; and wherein the polyolefin is a copolymer of ethylene and alpha olefin, wherein the alpha olefin comprises one or more selected from the group consisting of 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1,4-butadiene, 1,5-pentadiene, and 1,6-hexadiene. density, measured according to ASTM D1505, of 0.910 g/cm 3 to 0.930 g/cm 3; melting point, determined by DSC as set out in the specification, of 120 to 124°C; SCBs(Short Chain Branch), determined by 1 H NMR, per 1000 carbons of 1.0 to 5.0; and block comonomer distribution index(BCDI) calculated by the following Formula 1 of 1.0 or less: BCDI = ASL fi < 8 nm + ASL fi > 30 nm ASL fi 8 ∼ 30 nm in the Formula 1, ASL fi(<8nm) is the fraction(%) of chains having ASL (Average Ethylene Sequence Length) less than 8nm, by SSA (Successive Self-nucleation and Annealing) analysis, ASL fi(>30nm) is the fraction(%) of chains having ASL greater than 30nm, by SSA analysis, and ASL fi(8~30nm) is the fraction(%) of chains having ASL of 8 to 30nm, by SSA analysis; wherein the SSA is conducted using differential scanning calorimeter, by heating the polyolefin to the first heating temperature of 120 to 124°C, maintaining for 15 to 30 minutes, and then, cooling to 28 to 32°C, and while decreasing heating temperature by stages with (n+1)th heating temperature being 3 to 7°C lower than nth heating temperature, repeating heating-annealing-quenching until the final heating temperature becomes 50 to 54°C, and finally, raising the temperature from 30°C to 160°C; and wherein the polyolefin is a copolymer of ethylene and alpha olefin, wherein the alpha olefin comprises one or more selected from the group consisting of 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1,4-butadiene, 1,5-pentadiene, and 1,6-hexadiene. ASL fi(<8nm) is the fraction(%) of chains having ASL (Average Ethylene Sequence Length) less than 8nm, by SSA (Successive Self-nucleation and Annealing) analysis, ASL fi(>30nm) is the fraction(%) of chains having ASL greater than 30nm, by SSA analysis, and ASL fi(8~30nm) is the fraction(%) of chains having ASL of 8 to 30nm, by SSA analysis; wherein the SSA is conducted using differential scanning calorimeter, by heating the polyolefin to the first heating temperature of 120 to 124°C, maintaining for 15 to 30 minutes, and then, cooling to 28 to 32°C, and while decreasing heating temperature by stages with (n+1)th heating temperature being 3 to 7°C lower than nth heating temperature, repeating heating-annealing-quenching until the final heating temperature becomes 50 to 54°C, and finally, raising the temperature from 30°C to 160°C; and wherein the polyolefin is a copolymer of ethylene and alpha olefin, wherein the alpha olefin comprises one or more selected from the group consisting of 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1,4-butadiene, 1,5-pentadiene, and 1,6-hexadiene.