Continuous casting is a main process for the crude steel production, while the modeling and simulation serves an effective tool for the integrated computational materials engineering in the metallurgy. In order to predict and control the exit temperature of continuous casting slab, a three-dimensional model for the heat transfer and solidification during continuous casting has been developed based on the realistic roll apron and spray nozzle arrangement. Both cold and thermal state properties of the nozzle spray on the slab were considered, and the complicated boundary conditions, such as spray cooling, natural convection, thermal radiation as well as roll conduction were involved in the model. By calibrating the caster dependent model factor, the calculated cooling curve and solidification end accorded with the measurements. An example of modifying the process parameters showed that the thick slab temperature was effectively improved, which satisfied the requirement of the continuous casting production with sound quality.