Reincarnation of living Buddha is an important unique element in Tibetan Buddhism, and is indeed one of the crucial issues related to the “Tibetan Question”. In general, the legalization of the reincarnation has been witnessing a gradually deepening process. In 1793, the Qing court established the Golden Urn method and promulgated the 29-Article Imperial Decree for Better Governing in Tibet, marking the beginning of the legalization of reincarnation. In 1936, the Executive Yuan of the Republic of China approved Measures on the Reincarnation of Lamas which applied in peripheral regions outside Central Tibet. In 2007, the People’s Republic of China issued Measures on the Management of the Reincarnation of Living Buddhas that for the first time brought all the reincarnation systems in line with the rule of law. Historically, the legalization of reincarnation was the result of the game between secular regimes and Tibetan Buddhism sects. In essence, the legalization of reincarnation in modern China is rooted in a particular historical continuity since the Qing dynasty. The article aimed to develop a better understanding of the reasons underlying the legalization of reincarnation and provide the theoretical basis and factual basis for solving the current crucial issues surrounding reincarnation. It also discussed the crucial questions around reincarnation based on the legalization history of reincarnation.