The legal status of the 'Korean Provisional Government' of Shanghai(KPG) is a very interesting topic in terms not only of theoretical aspects but also of practical ones under international law. In short, the KPG is only a provisional government voluntarily constituted by political refugees fleeing abroad. It is problematic in that the KPG had no legal connection with the former 'Great Korean Empire'(GKE) and was a voluntary political organization in spite of its external proclamations. In consequence, it could not be regarded as a government in exile. Right after its foundation, the KPG tried to get formal or de jure recognition from foreign governments in China, Europe and the United States. Notwithstanding its strenuous efforts, the KPG was not recognized as a de jure government in international society as a whole except a small number of countries. Generally speaking, it was treated in reality as a 'de facto government.' Some people contend that a new nation building was made through the establishment of the KPG. But a political entity KPG was trying to represent had not fully satisfied the constituent elements of a state, namely, a permanent population, a defined territory, an effective government, capacity to enter into relations with the other states. In this viewpoint, the so-called theory of 1919 Nation Building of Republic of Korea(ROK) cannot be duly supported under international law.