A genetic algorithm was used for coding the volume of cooling water in the secondary cooling zone based on the heat transfer model in realtime production. This was done to improve the dynamic control of the secondary cooling water in highefficiency continuous casting. The fitness function of multiobjective optimization in the algorithm is in accordance with the distribution of metallurgical criteria. The genetic algorithm was integrated with the metallurgical criteria and the heat transferring model to optimize the water distribution. These steps increase the distribution adaptability and improve its efficiency compared to the traditional optimization methods of solving multiobjective optimization and other nonlinear problems. Simulation using the process data of the No.2 slab caster in the Steelmaking Plant of Panzhihua Iron and Steel and onsite testing were carried out. The results show that the optimized distribution saves 2% of water than without optimization, while water distribution along the slab to the water gradually decreases in accordance with requirements for slab quality control.