Abstract：Alliance was the enduring phenomenon under anarchy and also one of the key issues of studies in the field of international relations. The dominant state in the process of power transition invariably tries to adopt the alliance strategy for maintaining its dominance. In the transition of power, however, the dominant state is faced with stronger structural pressure, and demonstrates greater strategic dependence on allies. Therefore, it becomes much more difficult for the dominant state to manage and control its allies. At the same time, the alliance strategy of dominant state promotes existing alliance network to be more complex which increases the possibility that the dominant state would be drawn into international conflicts. The declining dominant state would progressively lose dominance once a great war breaks out, whether ends with a victory or defeat. The United Kingdom abandoned the policy of Splendid Isolation and turned to the alliance strategy in the early 20th century. The July Crisis in 1914 was a regional conflict between AustriaHungary and Serbia. Nevertheless, the alliance strategy of the United Kingdom neither restricts allies, nor deters rivals. In the context that Russia, France and Germany were gradually involved in crisis, the United Kingdom, which didnt pay much attention to the crisis, could not refrain from being drawn into the conflict, and the World War I seriously weakened the United Kingdom. In the postwar reconstruction, the United Kingdom had no choice but to share dominance with the France and the United States. It turns out that the alliance strategy didnt act effectively in maintaining the dominance of the United Kingdom.