During World War II, the two sides formed an alliance because of the common anti-fascist goal and jointly fought against fascism. However, after the war, due to the fundamental opposition of ideology and the struggle for world hegemony, the United States and the Soviet Union began to move toward opposition. From 65438 to 0947, the United States implemented the Marshall Plan to prevent Europe from "communism". The Soviet Union threw out the "Economic Mutual Assistance Committee" in the confrontation. 1949 The establishment of NATO marked the beginning of the Cold War between the United States and the Soviet Union, while the establishment of the Warsaw Pact in 1955 marked the final formation of the bipolar pattern in the world. The Korean War in 1950s, the Korean War and the Vietnam War that broke out in 1960s and 1970s were actually regional conflicts under the background of the Cold War. The lowest point of US-Soviet relations can be said to be the "Cuban Missile Crisis" that occurred in 1962. The two sides were once ready to launch a large-scale nuclear war.

Before the 1970s, the Soviet Union was always at a disadvantage economically and militarily, so the United States gained the upper hand. 1962 "Cuban Missile Crisis" ended with the Soviet Union's missile withdrawal, which shows that the Soviet Union still cannot compete with the United States in comprehensive strength. However, after Brezhnev came to power in the 1970s, the Soviet Union's military strength generally caught up with that of the United States because the United States was deeply involved in the Vietnam War. At that time, 1 of every three scientists in the Soviet Union were studying missiles and tanks. In the 1980s, President Reagan put forward the "Star Wars" plan and launched an all-round military competition with the Soviet Union. The Soviet Union was finally dragged down because of the war in Afghanistan and the defects of its own system, and announced its disintegration in 199 1.

Generally speaking, the post-war relationship between the United States and the Soviet Union was a change from a wartime ally to a hegemonic opponent. With the disintegration of the Soviet Union and the collapse of the bipolar structure, this relationship disappeared.