Abstract: For solving the slab location decision problem with hybrid stowage, a slab location model using a membership function was built to express the level of matching on the related attributes of length, width and thickness between the storing slabs and stored slabs in a warehouse. According to the characteristics of the problem, a hybrid discrete particle swarm algorithm, called DPSO-MC, was proposed based on crossover and mutation in genetic algorithms. Experimental results on a real case of a steel plant demonstrate that the model and algorithm are feasible and effective.