<p>The precise control of nanoprecipitates is crucial for achieving a balanced enhancement of both strength and ductility in maraging steel. In this study, a cobalt-free maraging steel with a grade of 2 GPa was successfully developed through an integrated approach that combines theoretical calculations with experimental validation. The results indicate that the steel variant containing only the Ni₃Ti precipitate exhibits both high strength and excellent ductility. Although the presence of the Mo-rich phase can significantly improve work hardening capacity and strength, it concurrently leads to a notable reduction in ductility. Transmission electron microscopy (TEM) characterization and theoretical analysis reveal that the formation of the NiAl and Mo-rich phases in aluminum-containing steel, along with the substantial lattice distortion it induces, is the primary factor contributing to the degradation of ductility. In contrast, the titanium-containing steel variant benefits from a low lattice mismatch between the semi-coherent Ni₃Ti precipitate and the matrix. The formation of a dense dislocation structure during plastic deformation, and the synergistic interaction between nanoprecipitates and residual austenite, enable the steel to achieve significant strength enhancement while maintaining satisfactory elongation. This study not only elucidates the underlying mechanisms of strengthening in maraging steel, but also provides a scientific foundation for compositional design in the development of high-performance steels.</p>