The irregular tribal military forces of Iran, which at the beginning of the Qajar era were disorganized in administrative, training, armament and uniform affairs, after the development of Iran-West relations and the arrival of European officers in Iran, were adorned with new equipment, techniques and uniforms, which completely transformed the troops. The main purpose of the present article is to study how the design and change of Qajar military uniform transformed military forces. Therefore, this paper attempts to answer this question “ What factors did contribute to the change of uniform in irregular Iranian military forces during Qajar era? ” In response to this question, one can put forth the hypothesis that following the defeat of Iran in the war with Russia, the uniform of irregular military forces of Iran was changed in a bid to establish a regular army and improve military power, integrity, mobility, style, speed and agility in execution of tasks. The research method adopted in this research is historical, which relies on the description and comparison of historical data. The results of the research suggest that factors such as war, communications, Qajar kings’ trips to the Europe, the necessity of transition from irregular tribal squads to a new regular army and the visits of Europeans officers from Iran have had the greatest impact on changing military uniforms.