A high-strength steel sheet comprising, by weight %, carbon: more than 0.25% to 0.75%, silicon (Si): 4.0% or less, manganese (Mn): 0.9 to 5.0%, aluminum (Al): 5.0% or less, phosphorus: 0.15% or less, sulfur: 0.03% or less, nitrogen: 0.03% or less, and a balance of iron (Fe) and inevitable impurities, wherein a microstructure comprises, by volume %, 30 to 75% of tempered martensite, 10 to 50% of bainite, and10 to 40% of retained austenite, 5% or less of ferrite, and an inevitable structure, wherein the high-strength steel sheet satisfies the following Relational Expression 1, 0.55 ≤ Si + Al γ / Si + Al av ≤ 0.85, where [Si+Al]γ is a content in weight% of Si and Al contained in the retained austenite, and [Si+Al]av is a content in weight% of Si and Al contained in the high-strength steel sheet, wherein the high-strength steel sheet optionally further comprises at least one of to: at least one of titanium (Ti): 0 to 0.5%, niobium (Nb): 0 to 0.5%, and vanadium: 0 to 0.5% at least one of chromium (Cr): 0 to 3.0% and molybdenum (Mo): 0 to 3.0% at least one of copper (Cu): 0 to 4.5% and nickel (Ni): 0 to 4.5% boron: 0 to 0.005% at least one of calcium (Ca): 0 to 0.05%, a rare earth element except yttrium: 0 to 0.05%, and magnesium (Mg): 0 to 0.05% at least one of tungsten: 0 to 0.5% and zirconium (Zr): 0 to 0.5% at least one of antimony (Sb): 0 to 0.5% and tin (Sn): 0 to 0.5% at least one of yttrium: 0 to 0.2% and hafnium (Hf): 0 to 0.2% cobalt (Co): 0 to 1.5%, and wherein a product of tensile strength and elongation (TS x El) is 22,000MPa% or more, and R/t is 0.5 to 3.0, where R is a minimum bending radius in mm at which cracking does not occur and t is a thickness in mm of the steel sheet, after a bending test. wherein a microstructure comprises, by volume %, 30 to 75% of tempered martensite, 10 to 50% of bainite, and10 to 40% of retained austenite, 5% or less of ferrite, and an inevitable structure, wherein the high-strength steel sheet satisfies the following Relational Expression 1, 0.55 ≤ Si + Al γ / Si + Al av ≤ 0.85, where [Si+Al]γ is a content in weight% of Si and Al contained in the retained austenite, and [Si+Al]av is a content in weight% of Si and Al contained in the high-strength steel sheet, wherein the high-strength steel sheet optionally further comprises at least one of to: at least one of titanium (Ti): 0 to 0.5%, niobium (Nb): 0 to 0.5%, and vanadium: 0 to 0.5% at least one of chromium (Cr): 0 to 3.0% and molybdenum (Mo): 0 to 3.0% at least one of copper (Cu): 0 to 4.5% and nickel (Ni): 0 to 4.5% boron: 0 to 0.005% at least one of calcium (Ca): 0 to 0.05%, a rare earth element except yttrium: 0 to 0.05%, and magnesium (Mg): 0 to 0.05% at least one of tungsten: 0 to 0.5% and zirconium (Zr): 0 to 0.5% at least one of antimony (Sb): 0 to 0.5% and tin (Sn): 0 to 0.5% at least one of yttrium: 0 to 0.2% and hafnium (Hf): 0 to 0.2% cobalt (Co): 0 to 1.5%, and at least one of titanium (Ti): 0 to 0.5%, niobium (Nb): 0 to 0.5%, and vanadium: 0 to 0.5% at least one of chromium (Cr): 0 to 3.0% and molybdenum (Mo): 0 to 3.0% at least one of copper (Cu): 0 to 4.5% and nickel (Ni): 0 to 4.5% boron: 0 to 0.005% at least one of calcium (Ca): 0 to 0.05%, a rare earth element except yttrium: 0 to 0.05%, and magnesium (Mg): 0 to 0.05% at least one of tungsten: 0 to 0.5% and zirconium (Zr): 0 to 0.5% at least one of antimony (Sb): 0 to 0.5% and tin (Sn): 0 to 0.5% at least one of yttrium: 0 to 0.2% and hafnium (Hf): 0 to 0.2% cobalt (Co): 0 to 1.5%, and wherein a product of tensile strength and elongation (TS x El) is 22,000MPa% or more, and R/t is 0.5 to 3.0, where R is a minimum bending radius in mm at which cracking does not occur and t is a thickness in mm of the steel sheet, after a bending test.