The article is devoted to the study of factors influencing decision-making by the commander under non-predetermined conditions in terms of training of servicemen in higher military educational institutions. The problem is considered from the standpoint of the future commander's capacity building in his moral, professional and personal components. The psychological factors that determine decision-making in conditions of uncertainty are highlighted. The cadet's research contained the following diagnostic and corrective techniques: J. Kelly's test with a role construct of a decisive and indecisive commander to identify personality traits that identify a commander who has the ability to act decisively under non-predetermined conditions, a dynamic method of psychom drawing "Symbol of one's own life" identification of features of value orientations and features of characteristics of thinking in a projection of development of own being; expert description of the commander's decision-making in a situation with uncertain conditions. In a special process to promote the organization of the influence of factors that help decision-making in uncertain conditions (trust in the commander, the relationship of brotherhood), showed its effectiveness (t-Student t = 5,71 at p<0,05 between the two groups at the end of the experiment at t-Student t = 2,28 at p> 0,05) it is possible to achieve a higher level of training of the future officer. The scientific novelty of the obtained research results is as follows: 1) Improved methodological approach to the formation of readiness for management decisions in extreme conditions; in conditions of uncertainty, taking into account the peculiarities of the analyzed unit, rational and irrational in the moral and psychological state of the individual and group; 2) The method of optimization of decision-making in the conditions of uncertainty which consists in the analysis of the information on the person and division in which it serves, a substantiation of the project of development of psychological structure of collective and the interconnected structure has received further development. Thus, the commander's decision-making under non-predetermined conditions can be considered from a situational approach, when at a certain time, taking into account the level of psychological readiness, the commander decides "for battle", as well as from the systemic, structural and functional, when the training system contains long ontogenetic development of the soldier's personality in his physical, psychophysiological, moral, spiritual directions.