This dissertation is a documentary research, which has three objectives:（1）to study Ānāpānasati in the Visuddhimagga, especially its sixteen bases and eight stages (2) to study Ānāpānasati in the Vimuttimagga (3) to study and compare Ānāpānasati in two treatises with their common bases and find the contribution of them. The technique in this dissertation involves the particular way or special skills. For the purpose to study Ānāpānasati, this dissertation used the Chinese resource and put both two treatises into their own background. After the study of meditation in them, the main skills of Ānāpānasati contented in the process of sixteen bases and several stages. For the purpose to explain, the dissertation explores the related knowledge and ancient scriptures.
The description of Ānāpānasati in the Visuddhimagga is more precise and systematic than the Vimuttimagga. In Chinese scriptures, the Vimuttimagga is the first treatise to establish the theory of meditation sign.The dissertation explored the eight or four stages of Ānāpānasati in two treatises and emphasize the meditation sign, the key to achieve different jhāna. In the theory of meditation, both two treatises have the structure of four foundations of mindfulness. As the core teaching of meditation, Ānāpānasati in these two treatises has its special significance for the construction of Buddhism.