Abstract: To determine the water consumption in the secondary cooling zone during continuous casting, which will affect the internal quality of CC billets, a new approach is proposed to it on the basis of particle swarm optimizer (PSO). A mathematical model of solidification process is thus developed according to the principle of solidification with volume controlled, and the model is verified by measuring billet shell thickness through nail shooting and sulfur printing. Then, the flattening temperature, reheating temperature and its rise/drop limits are taken as objectives in the artificial intelligent PSO to optimize the water consumption in the secondary cooling zone during continuous casting. Applying the model to the steel Q235, the results showed that the core crack is improved to Grade 0.5 from 1.5 with porosity rate reduced by 7.2% and cracks reduced by 3.6%. It shows the effectiveness of the model.