Knowledge management (KM) is suggested as a method to manage and apply knowledge for business management. In this paper, we suggest a framework based on OPF (Open Process Framework) meta model for the knowledge-based decision-making. Based on the modeling method of OPF, we can translate partial and implicit knowledge resident in an individual's mental model into organized explicit knowledge. The demonstration steps of the organized knowledge model enable decision-makers to understand the structure of the target problem and identify the basic cause of it, which facilitates effective decision-making. Finally, we study knowledge management behaviors during decision making.