A long-standing challenge in materials science is the trade-off between strength and ductility in steel. This study presents a method to enhance the strength of twinning-induced plasticity (TWIP) steel without compromising ductility. By applying torsion to cylindrical TWIP steel samples to create a gradient nanotwinned structure along the radial direction, the yielding strength of the material is doubled without reducing ductility. This is attributed to the formation of a gradient hierarchical nanotwinned structure during pre-torsion and subsequent tensile deformation. Finite element simulations based on crystal plasticity are used to understand how the gradient twin structure enhances strength and retains ductility, and how sequential torsion and tension lead to the observed hierarchical nanotwinned structure through activation of different twinning systems. TWIP steels, known for their high strength and formability, have been developed to meet the demands of modern vehicle components. However, their yielding strength is relatively low, and traditional methods for increasing strength often reduce ductility. This study shows that pre-torsion can create a gradient nanotwinned structure that enhances strength while maintaining ductility. The results demonstrate that the combination of gradient twin density and hierarchical nanotwinned structure significantly improves strength and ductility. The study also reveals that different twinning systems are activated during pre-torsion and subsequent tension, leading to a hierarchical twin network that enhances strength and ductility. The findings suggest that gradient hierarchical nanotwins can be used to enhance the strength of TWIP steel without sacrificing ductility. This method has potential applications in various industries, including mechanical, civil, aerospace, transportation, oil, and automotive. The study also highlights the importance of understanding the deformation mechanisms in TWIP steels, including the role of dislocations and twin boundaries in enhancing strength and ductility. The results demonstrate that the combination of gradient twin density and hierarchical nanotwinned structure can significantly improve the mechanical properties of TWIP steel, making it a promising material for structural applications.A long-standing challenge in materials science is the trade-off between strength and ductility in steel. This study presents a method to enhance the strength of twinning-induced plasticity (TWIP) steel without compromising ductility. By applying torsion to cylindrical TWIP steel samples to create a gradient nanotwinned structure along the radial direction, the yielding strength of the material is doubled without reducing ductility. This is attributed to the formation of a gradient hierarchical nanotwinned structure during pre-torsion and subsequent tensile deformation. Finite element simulations based on crystal plasticity are used to understand how the gradient twin structure enhances strength and retains ductility, and how sequential torsion and tension lead to the observed hierarchical nanotwinned structure through activation of different twinning systems. TWIP steels, known for their high strength and formability, have been developed to meet the demands of modern vehicle components. However, their yielding strength is relatively low, and traditional methods for increasing strength often reduce ductility. This study shows that pre-torsion can create a gradient nanotwinned structure that enhances strength while maintaining ductility. The results demonstrate that the combination of gradient twin density and hierarchical nanotwinned structure significantly improves strength and ductility. The study also reveals that different twinning systems are activated during pre-torsion and subsequent tension, leading to a hierarchical twin network that enhances strength and ductility. The findings suggest that gradient hierarchical nanotwins can be used to enhance the strength of TWIP steel without sacrificing ductility. This method has potential applications in various industries, including mechanical, civil, aerospace, transportation, oil, and automotive. The study also highlights the importance of understanding the deformation mechanisms in TWIP steels, including the role of dislocations and twin boundaries in enhancing strength and ductility. The results demonstrate that the combination of gradient twin density and hierarchical nanotwinned structure can significantly improve the mechanical properties of TWIP steel, making it a promising material for structural applications.