The Yemeni civil war, which has been deeply involved by countries in the region since March 2015, is moving toward separating Republic of Yemen into the two Yemeni states which had been before they were merged on 22 May 1990. In fact, the structure of the current conflicts was formed in the mid-20th century during political changes in North and South Yemeni states and the regional hegemony competition involving regional powers. Thus, to understand the current situation in the region, it is necessary to correlate the creation process of the two Yemen states and the role of the great powers that had an absolute impact on the process before it was incorporated into Republic of Yemen in 1990, and then to compare this with the current situation. The paper analyzes the process of the creation of two independent states in Yemen created after the withdrawal of the Ottoman Empire and the British Empire respectively, the civil war and the hegemonic struggle of the regional Powers