The research purposes of this paper are discussing the special connotation of the śūraṃgama-samādhi, and based on the Buddhist scriptures and treatises discussing the connection theory of the śūraṃgama-samādhi and the Buddha nature, the śūraṃgama-samādhi show the degree of the Buddha nature, as well as the important meaning of the practice of the Buddha nature. This study focuses on the theory and logic of the Buddhist scriptures and treatises, so research methods emphasize equally on philosophy and literature. The research results show that the śūraṃgama-samādhi is incompatible with the two vehicles of the śrāvaka and pratyekabuddha, and is unique to the bodhisattvas. The bodhisattvas of the stage of the dharma-cloud (dharmamegha-bhūmi ) completely get the śūraṃgamasamādhi. The śūraṃgama-samādhi is the accomplishment of practicing all the samādhi, and is the first and leader of all the samādhi, and heads up all the samādhi, and enters into and emerges at ease from all the samādhi. The Buddha nature contains all the Buddhist scriptures and the samādhi, encompassing the śūraṃgamasamādhi. The bodhisattvas gained the śūraṃgama-samādhi and the inconceivable connotation of the Buddha nature are revealed. The śūraṃgama-samādhi contains all the samādhi. The bodhisattvas gained the śūraṃgama-samādhi, and means all the samādhi are in place, and the prajñā-pāramitā that the śūraṃgama-samādhi enlighten are in place, and the innumerable pāramitā that related to the prajñāpāramitā are in place, so the immeasurable connotation of the Buddha nature is completely revealed. The process of practicing the śūraṃgama-samādhi is a series of the process of the mind training. There is a gradual the order to follow until the becoming Buddha. The process that the bodhisattvas practice the śūraṃgama-samādhi is the process that the bodhisattvas reveal the Buddha nature. The originalities and contributions of the research results: At present, scholars rarely study the connection of the śūraṃgama-samādhi and the Buddha nature. This paper including both theory and practice can provide the reference for future related research.
