This paper focuses on the process of creating the 1948 Constitution of the Republic of Korea in order to examine the legal interpretation of the “Inheritance of the Pop-tong (legitimacy or legal tradition, in Korean) of the Provisional Government of the Republic of Korea” addressed in the preamble to the Constitution of the Republic of Korea (1987 Constitution), based on materials left by Yu Chin-o, a Korean legal scholar who wrote the draft of the 1948 Constitution. Specifically, the importance of the preamble to the Constitution and the literal meaning of ‘pop-tong’ are examined. The memoirs and manuscripts of Yu Chin-o are then discussed, based on discussions in previous studies. The author points out in closing that it is difficult to conclude that Yu Chin-o gave consideration either to the pop-tong of the Provisional Government of the Republic of Korea or its inheritance by the Republic of Korea in his constitutional planning.