Continuous casting is a revolutionary technology of steel production. To guarantee the quality of steel, the solidifying process should be studied and controlled. Both theory and experiment have shown that excessive stress inside the stell strand, which results from thermal contraction, bending and bulging of the solidified shell, can cause internal and surface cracks. The bulging of the shell is in general a visco-elasto-plastic phenomenon couple with phase change. In this paper, the theory of elasticity is applied to study numerically the bulging behavior of the shell between consecutive supporting rollers. Considering the geometry of the steel slab, both heat transfer and stress analysis are simplified to two-dimensional problems. Furthermore, the heat transfer process can be treated independently of the deformation. With these simplications, numerical results are obtained.