Abstract: The three-dimensional deformation behavior of continuous casting blooms with soft reduction was theoretically characterized and quantitatively analyzed by the finite element method (FEM) under different soft reduction conditions. The results show that the longitudinal elongation ratio is proportional to the soft reduction amount after the balance between lateral spreading deformation and longitudinal spreading deformation. Under the same soft reduction condition, the lateral elongation efficiency and longitudinal elongation efficiency decrease with the increases in aspect ratio and non-solidification ratio of casting billets, whereas the reduction efficiency increases.