日本声称拥有钓鱼岛主权的法理依据,与其对有关国际条约的态度和立场密切相关。本文以日本开始主张拥有钓鱼岛主权的1895年为时间起点,来考察涉及钓鱼岛主权的国际条约。通过深入分析各历史时期涉及钓鱼岛主权归属的国际条约,认为钓鱼岛经由《马关条约》割让给日本,二战后依相关条约理应归还中国;日本无权以托管制度对抗中国的主权主张,而且其也在中日邦交正常化文件中承认了其应履行归还领土的条约义务。因此,日本应将钓鱼岛主权归还中国以履行其条约义务。 Japan claims to have the legal basis for sovereignty over the Diaoyu Islands and is closely related to its attitude and position on the relevant international treaties. In this paper, Japan began to advocate the sovereignty of the Diaoyu Islands in 1895 as a starting point to examine the Diaoyu Islands sovereignty of international treaties. Through in-depth analysis of the international treaties concerning the sovereignty of the Diaoyu Island in all historical periods, it is considered that the Diaoyu Island was ceded to Japan through the Treaty of Shimonoseki and should be returned to China under the relevant treaties after the Second World War. Japan did not have the right to confront China’s sovereignty with the trusteeship system, In its normalization of diplomatic relations between China and Japan, it recognized its obligation to fulfill the treaty of returning territories. Therefore, Japan should return the sovereignty of Diaoyu Island to China to fulfill its treaty obligations.