The contractor management for the effective defense project is essential factor in the modern defense acquisition task. The occurrence of unlawful company causes hastiness for project manager and setback to the deployment of defense weapon system. In this paper, we develop a prediction model for the effective defense project by using the discriminant analysis and analyse the variables that discriminate the unlawful company in many variables. It is expected that our model can be used to improve the project management capability of defense acquisition and contribute to the establishment of efficient procurement procedure through entry of the reliable defense manufacturer.