The purpose of this paper is to develop intelligent advanced fighter air combat decision support system (IAFACDSS). IAFACDSS will generate the best strategy for advanced fighter's pilot in an air combat environment. In the IAFACDSS, we use fuzzy inference system (FIS) as decision-making mechanism that takes into account of human thinking ability and pilot physical limitations. Before executing FIS process, every future posture corresponding to pilot's decision-making space of advanced fighter and an enemy's fighter future posture must be predicted. This paper assumes that IAFACDSS will accurately predict an enemy fighter's future posture. Then IAFACDSS applies the predicted data to generate the best control command through FIS. We verify the proposed algorithm with a set of fighter flying data that is used as enemy fighter's flying trajectory. The simulation results show that IAFACDSS will enable advanced fighter to obtain the best status in an air combat environment, thus effectively achieving the object for developing IAFACDSS