The solidification structure was simulated by the commercial software CALCOSOFT under the real cooling condition during the continuous casting processes in this paper. The cellular automation-finite element model (CA-FE) was applied to simulate the microstructure of the slab, and the results were compared with the actual macrostructure. The results of microstructure simulated were in good agreement with that detected in the slabs. In addition, the solidification structure under different secondary cooling intensity was simulated. The results show that when specific water flows increase, the average grain surface area reduces, and columnar grains have the tendency to be longer. The solidification structure was simulated by the commercial software CALCOSOFT under the real cooling condition during the continuous casting processes in this paper. The cellular automation-finite element model (CA-FE) was applied to simulate the microstructure of the slab, and the results were The results of microstructure simulated were in good agreement with that detected in the slabs. In addition, the solidification structure under different secondary cooling intensity was simulated. The results of that specific that when specific water flows increased, the average grain surface was area reduces, and columnar grains have the tendency to be longer.