This paper, mainly based on Mahābherīsūtra, analyzes the structure of tathāgatagarbha in order to clarify the meaning of mahāparinirvāṇa. Tathāgatagarbha, with its dual aspects of removing kleśa and attaining Buddhahood, is suitable for interpreting the “veiled statement” of Mahāparinirvāṇa, that is, “Tathāgata has entered parinirvāṇa and being everlasting, never extinct.” This paper proposes that the “veiled statement” uses freely the terms “permanent / impermanent” and “ātman / anātman”, attempting to bring out the dynamic and multi-layered meaning of mahāparinirvāṇa. Nonetheless, such switching usages make it more difficult to understand the veiled statement. Therefore, this paper attempts to unravel the rich and diverse connotations of mahāparinirvāṇa in the Mahābherīsūtra by means of the idea of tathāgatagarbha. In brief, the “permanence of tathāgata” brings out a doctrine of the mahāparinirvāṇa practice with the phased teaching strategies of “ātman / anātman” in the Mahābherīsūtra. The “anātman” focuses on the understanding of emptiness of worldly affairs for removing kleśa, thus expressing the pure liberation of the dharmakāya and nirvāṇa. On the other hand, the “ātman” focuses on the dharmakāya of the tathāgata, which brings out the realm of mahāparinirvāṇa, the real peace of the eternal and indestructible. These two complement each other and constitute together the doctrine of mahāparinirvāṇa. Through the above analysis, this paper has obtained several outcomes that can help advance the study of tathāgatagarbha. Firstly, there is not necessarily opposition between “ātman” and “anātman in tathāgatagarbha. Rather, it could actually bring out a comprehensive description by means of unifying them. Secondly, by distinguishing the similarities and differences between mahāparinirvāṇa and the other parinirvāṇa, it could explore the profound meaning of the mahāparinirvāṇa. Thirdly, the doctrines of parinirvāṇa might unite under the ekayāna, namely Mahāyāna, so that mahāparinirvāṇa would be the ultimate one among the various types of parinirvāṇa.
