Abstract: To address the demand for high strength and toughness of S460 steel in complex marine environments, the effects of non-recrystallization zone rolling temperature, pass reduction rate, and holding thickness on microstructure and mechanical properties were investigated through ultra-purified smelting combined with thermo-mechanical controlled processing. The results indicated that reducing the rolling temperature in the non-recrystallization zone to 812℃ was found to promote grain refinement and dislocation strengthening, with the yield strength being elevated to 610.47MPa. At the same time, more quasi-polygonal ferrite was formed, improving both plasticity and toughness. When the pass reduction rate was raised to 26.0%, the amount of bainite and nano-sized particle precipitation increased, but the impact energy at -80℃ dropped to 142J, The optimal balance between strength and low-temperature toughness was achieved at a holding thickness of 40mm. This study demonstrates that the strengthtoughness synergy in S460 steel can be controlled by tailoring grain refinement, dislocation density, and precipitate distribution via TMCP, providing a robust process design basis for efficient manufacturing of offshore wind power structural steels.