Abstract: The manufacturing flow between steel-making and continuous-casting, which is a complex multistage and multi-product production process, was modeled using colored Petri nets. The model had characteristics of graphic representation and easily analyzing the model properties and model performance. Two important modeling problems were discussed:different guard functions were placed in different transport transitions to implement route selection, and the input and output function of a single procedure transition was programmed to realize different processing time for different products. The bounded constraints were verified and the solution method to get the best makespan was proposed based on occurrence graphs. The effective method was shown by an applied instance.