In this study, we used several policy change models, including Kingdon's policy flow model, to analyze changes in Korea's population policy and examine which changes had the greatest impact. As a result, political factors were found to play the most important role in policy change and decision-making. Until the 1960s, Korea had the highest population growth rate in the world, which led to serious economic and social problems. Accordingly, President Park Chung-hee and President Chun Doo-hwan, who came to power through a military coup, implemented a birth control policy to solve the rapidly increasing population problem. As a result, although it succeeded in lowering the birth rate, Korea has recorded the world's lowest birth rate for 15 consecutive years. A study conducted in 2005 during the Roh Moo-hyun administration warned that Korea could face a serious crisis if the birth rate continues to decline. Accordingly, President Roh Moo-hyun changed his policy stance from suppressing births to encouraging childbirth. However, despite the government's large-scale investment, the total fertility rate continued to decline, making recovery difficult. In other words, the policy to increase the birth rate failed, and this can be seen to be due to an error in the policy decision-making process. This phenomenon can be explained by the political flow of the Kingdon model. In Korea, the president sets policy direction, and various policymakers, including the ruling party and the executive branch, implement the policy according to the president's instructions. This shows that the president's role is decisive in the process of policy formation and implementation. In fact, in Korea's population policy, the president's will and activities had the greatest influence on policy outcomes.