The RoK-U.S. SMA has been repeated every year from the first agreement between the United States and The Republic of Korea in 1991 to the 11th Agreement in March 9, 2021. Of these, the 11th Agreement was finalized on March 10, 2021 after a year and six months after the official start of negotiations between the two countries in September 2019. Specifically, the 11th Agreement began under the U.S. Trump administration, but as disagreements between the United States and the United States were sharply opposed, they failed to make a solution, but rather in the Biden administration, they quickly reached an agreement. Accordingly what discriminatory negotiations has the South Korean government had in negotiating SMA with the U.S. Trump-Biden administration? In terms of our negotiating behaviors, I tried to analyze each negotiation strategy. As a result, the Trump administration, the Biden administration, and South Korean government were different among their own negotiating behaviors or approaches(relative recognition, negotiation object, negotiator attitude, negotiation strategy), and in particular, the increased negotiating power of the Rok Government was conspicuous according to the increased national power.