The production process of a refinery is a complicated process, which consists of immense units. For some units, the products are multiple, so does the feasible operation mode of products of certain units. Which kind of operation mode is utilized decides the production strategy of a refinery. In this paper, how to gain reasonable production strategy is focused on due to the immense benefit it can bring to, and a production strategy optimization model based on mixed bi-level programming method is presented to solve this problem. All the units included in the production process are divided into two levels, and most of the production information of them is integrated by a database system in the model. How the optimization model can be used as a viable tool is also showed by a simple case study at Daqing refinery