On august 2, 2011, President Obama signed the budget control act of 2011, which would cut spending for the next decade in exchange for raising the debt ceiling. The bill not only opened the way for the US defense budget to decline, but also had a great impact on the US defense policy. In august 2019, the US Congress passed the bipartisan budget act of 2019, which raised the defense budget ceiling for fiscal year 2020-2021, in fact repealing the effect of the BCA in advance. Through tracking the data of the US defense budget in the past 8 years, this paper analyzes the overall impact of the BCA on the US military from three aspects: the current situation of the U.S. military, strategic adjustment and countermeasures. In particular, byobserving the U.S. military in a period of low budget, this paper summarizes the characteristics and rules of its countermeasures to offset the shortage of budget by applying technological advantages, thus providing reference for the study of future national defense policy trend of the U.S. military