The contractor management is one of the important factors for the modem defense acquisition program. The occurrence of unlawful company causes the reason in which defense acquisition program is unable to be reasonably fulfilled and setback to the deployment of defense weapon system. In this paper, we propose the Artificial Neural Network to develop a prediction model for the discrimination of unlawful company in defense procurement. The data which are used in analysis, are obtained targeting domestic small & medium manufacture enterprises. It is expected that our model can be used to improve the program management capability for defense acquisition and contribute to the establishment of efficient procurement procedure through entry of the reliable domestic manufacturer.