The purpose of this article is to analyze the background of the Myanmar’s military(Tatmadaw) coup on February 1, 2021, based on the military’s internal and external environment, and to explore dynamics of competition and conflict between the military and the people. In detail, it is intended to focus on the fundamental reasons why the old institution such as the military seizes political power and the people’s resistance to the coup under the situation which has undergone a short process of democratization, In doing so, it focus on verifying the factors that inevitably led to the coup in perspective of the the civilian-military relationship replacing with the structure and the agency. If we understand the civilian-military relationship that had been solidified internally, we could trace the reason of the military coup, interpretation of a subsequent situations that have taken place after the coup, and prospect of the political development.BR The military has enjoyed “reserved domains” in the areas of administration and legislature based on the Constitution, but the level of military control by the civilian government was relatively higher than that of the administration. Being conflicts and cracks among the nationals, such as Sangha, ethnic Burman and the ethnic minorities, the older and the MZ generations, and the existence of dalang which is a supporting group to the military, it was not able to make collective resistance against the military. Furthermore, it is sure that the military, which lost its self-control, staged acoup to defend collective interests under the weak situation of vertical and horizontal control by the civilian government.BR In conclusion, achieving democratization at the institutional level seems to be a long way off, unless the military voluntarily returns to the barracks. Although the military returns to the barracks or democratic bloc restores democratization, if the principle of civilian supremacy over the military will not be realized, then the future of democracy will not be bright. Therefore, strategy for civilian supremacy over the military should be promoted as a mid and long term task, and civil society should choose and promote national reconciliation and integration as its top priority before solidifying democracy’s confidence through strengthening its internal capabilities.