War field differs from conventional military education and training environments. Warfighter may confront frequently unexpected physical and psychological stimulation. Cumulative psychological stress and physical fatigue can be causes of mood distortion, declined alertness, and decreased combat capability in warfighters. Countermeasures of combat stress and fatigue is very important for keeping combat capability and saving of life. Here in, the countermeasures of combat stress and fatigue have reviewed, and limitation and the direction of research and development of countermeasures of combat stress and fatigue are proposed.