Abstract: In his old ages, the issue of choosing a successor became a key flash point that ignited a series of internal and external conflicts and problems in the sangha. The issue was not only constrained by the conflicts between Shakya monks and Brahman monks, but also was closely related to the struggle between Buddhism and Jainism. The Buddha was in a dilemma and failed to make the final decision. The fact that the records in sutras seem to avoid this issue intentionally makes the issue particularly perplexing and complicated. This paper makes preliminary investigation by analyzing carefully documents and historical texts. It aims to reveal the actual situation in the ancient Buddhist circle in India and to put forward the author’s own opinion.