In order to increase production efficiency at open-pit mines, on the basis of linear programming, a practical mathematical model for optimizing truck flow was developed, which improved the traditional fixed manual schedule method. The model has advantages from linear programming and objective programming, makes most handling points working at full capacity and keeps an optimized ratio between trucks and excavators. For ensuring feasibility of the model in practical production, four standards for feasibility test were proposed. The model satisfied all the standards. The application in a large scale open-pit iron mine indicated that the model reduced the number of required trucks by 10% compared with the fixed manual schedule method.