<p>Macro/semi-macrosegregation in gear steel significantly impacts the mechanical properties of the final product, markedly exacerbating heat treatment distortion in gears under extreme conditions. In this study, the central segregation (CS) and spot segregation of 20CrMnTiH gear steel continuous casting bloom, the central segregation, and banded defects of rod and their mechanical properties were analyzed experimentally, and the homogeneity control mechanism and strategy for 20CrMnTiH blooms and rods during continuous casting full process were proposed. The results indicate that the equiaxed ratio in the continuously cast blooms significantly decreased and the size of equiaxed crystals was reduced under the optimized full process [involving high superheat, weak mold electromagnetic stirring (M-EMS), and soft reduction (SR) at the solidification end]. This resulted in the alleviation of central segregation, a significant reduction in the carbon range and standard deviation across sections, and a marked decrease in the size, number, and concentration of C, Cr, and Mn in the spot segregations. Correspondingly, the equiaxed ratio in the rod also significantly decreased, central segregation was alleviated, and there was a substantial improvement in the carbon range and standard deviation across the rod sections, the number of large-sized banded defects, and the concentration of C, Cr, and Mn solutes is significantly reduced, enhancing the radial direction (RD) plasticity and toughness of the rod. This indicates that the full process optimization, involving high superheat, weak M-EMS, and SR at the solidification end, can synergistically regulate the macro/semi-macro homogeneity of gear steel blooms and rods, with particularly significant improvements in semi-macro homogeneity.</p>