Abstract: This study takes the soft reduction process during continuous casting of large square blooms (325 mm × 280 mm) at a steel plant as the research object. Reduction models were established for different combination modes of flat rolls, convex rolls, right-angle blooms, and chamfered blooms. The distribution of equivalent strain on the bloom surface and the strain transfer efficiency in the thickness direction were investigated through numerical simulation, with the effectiveness verified by industrial trials. The results show that: convex rolls optimize the surface strain distribution of the bloom, reduce corner strain magnitude, improve stress conditions at the corners, and decrease crack occurrence. Chamfered blooms exhibit superior strain transfer efficiency in the thickness direction compared to right-angle blooms, with efficiency increasing from 13.3%～14.7% to 43.2%～50%. Convex rolls outperform flat rolls in strain transfer efficiency, efficiency increases from 13.3% to 14.7% for right-angle blooms and from 43.2% to 50% for chamfered blooms. Industrial trials demonstrate that applying flat rolls to chamfered blooms significantly improves core quality. Furthermore, the chamfering method of the cast billet has a more significant effect on improving the macrosegregation of the billet compared to the convex roller pressing method.