We designed a knowledge-based decision support system for structuring semi-or unstructured problems. Problem structuring involves extraction of the relevant factors from the identified problem, and model construction that represents the relationships among those factors. In this research, we employed a directed graph called Influence Deiagram as a tool for problem structuring. In particular, our proposed system is designed as a shell. Therefore, a decision maker can change the content of the knowledge base to suit his/her own interested domain.