The management systems of defense projects need to be well-maintained because of huge cost and long-terms of acquisition & operation in conducting defense acquisition. In this paper, we use a structural equation model(SEM) to develop an project management index(PMI) for effective defense project. The concept of a customer satisfaction index is used to assess the PMI for strategic improvement plans for various characteristics of project management. It is expected that our model can be used to evaluate and improve the project management capability of defense acquisition.