Abstract The military is the foundation of a nation¡¦s safety. To ensure the safety, prosperity and a continuous development of a country, the commanding officer of each troop in the armed forces should adopt a kind of leadership which can meet the needs of a country and its people thus fulfilling the mission of defending a country and protecting its people. The writer thoroughly observed and interviewed two commanding officers who were the subjects of this case study. The study is aimed to discuss the leadership behavior of the air-force colonels who are commanding officers. The study discusses the organization structure, the characteristics of missions and the number of people in troops, the difference between the leadership behavior between the commanding officers. The study tries to find a suitable leadership behavior which can be served as a reference for commanding officers in different troops in the future. The study has found the following phenomenon: 1. To lead a huge organization which has many people and facilities and units, the most important job is to know how to control. To lead an organization which has less people and it has a professional unit, the most important job is to plan and to know how to communicate to the subordinates. 2. There are many unnecessary meetings in the troops. The meetings are too long. Only a few items need to be discussed are relevant to the units, so it is a waste of time. 3. Due to different units, some commanding officers have too much work, some have less work. Some can not fully use his talents. Responsibility and power do not match. 4. If the unit has less people and resources, the conflict between subordinates are less. If the leader has better skill of eloquence, he can persuade his subordinates and convince them easily. 5. The leadership behavior at this stage in the military is ¡§people-centered¡¨ which produces good effects in leadership. In summary, the leadership behavior of the commanding officer can directly influence the behavior and attitude of his subordinates. The more the commanding officer cares his subordinates, the better meets the psychological needs of his subordinates. Key Words: Leadership behavior and effectiveness, 4 diagrams of leadership behavior,System and person-oriented, Initiating and consideration structure,Situational factors.