Abstract: While traditional production organization uses a fixed assignment of truck, the optimized dispatching system uses a flexible assignment of truck in open pit.Both of them have advantages and disadvantages, and the previous research does not balance them effectively.To implement an optimized assignment for the needs of fixed assignment of truck, this paper discussed the situation by dividing it into three types:fixed truck, fixed truck model, fixed unload site for an open-pit mine.A universal mathematical traffic flow model was proposed on this basis, which is compatible to various needs for the assignments of truck, including:fixed truck, fixed truck model, fixed unload site and optimized assignment.Meanwhile, the differences of using four types of independent applications under different situations were discussed.The results showed that the optimized assignment gave the best result, then followed by fixed truck, fixed truck model and fixed unload site.According to the results, some suggestions have been made to mine production.The model gave access to program truck flow for fixed truck, fixed truck model, fixed unload site and optimized assignment both in coordination and individual, with an excellent compatibility, extensibility, versatility and practicality.