To solve the lack problems of overall planning and information management of precast concrete components stacking in prefabricated construction site, a mathematical model for the packing optimization was established based on the analysis of the site stacking scheme and the hoisting distance of precast concrete components. The solving method for the model was proposed based on the genetic algorithm and the surplus rectangle algorithm, and a packing optimization system was developed. The packing optimization system could be used for both the stackable condition and the non-stackable condition by providing the optimum scheme including the stacking position and the stacking order with the minimum hoisting distance. Moreover, the management process of precast components is clear, and managers can arrange the precast packing according to the optimum scheme. A case study demonstrates that the optimization system improves the management level and hoists the efficiency of precast. Meanwhile, it can reduce the reliance on the site management experience and realize the information management of precast.