The concept of Dvādaśāṅga Pratītyasamutpāda (twelve Nidānas)is the basic doctrine of Buddhism that is commonly known in both Mahāyāna and Hīnayāna Buddhism. Moreover, in original Buddhism, twelve Nidānas were divided into two parts, transformation and development, which were observed by applying positive and negative Vipaśyanā. This kind of practice was relatively plain and original. By the time there was Mahāyāna Buddhism, in Ten Bhūmis of Avataṃsaka Sūtra, the origin of Dvādaśāṅga Pratītyasamutpāda was attributed to “the all twelve branches are generated from one mind”; this means the study of Dvādaśāṅga Pratītyasamutpāda became a study of “Pratītyasamutpāda of one mind”. With the concept of “Pratītyasamutpāda of one mind”, offered in Ten Bhūmis of Avataṃsaka Sūtra, stating that the one mind is the origin of all Dharmas in the universe, mind of the beings is thus explained in different aspects. This makes Mahāyāna Buddhism become idealistic theories, and has a great impact on Chinese Buddhist schools. Nonetheless, it has always been a critical issue attracting great concerns in academic fields to discuss whether such a mind is truthful or delusional. As the theme of this thesis is the development of Origins in Huayan school, four versions of assumptions shall be referred following the orders of time. The first is Pratītyasamutpāda in Ten Bhūmis of Avataṃsaka Sūtra that is divided into the origin of Dvādaśāṅga Pratītyasamutpāda and twelve Nidānas in Ten Bhūmis of Avataṃsaka Sūtra. The second is Pratītyasamutpāda in Treatise on the Daśabhūmika Sūtra, which is divided into three insights of the difference of two truths(satya), paramārtha-satya, and saṃvṛti-satya. Following that is the idea of Pratītyasamutpāda that Fazang stated, which is divided into the “holding” of Ten Bhūmis of Avataṃsaka Sūtra, and the interpretations of Treatise on the Daśabhūmika Sūtra. Last but not least, the idea of Pratītyasamutpāda of Chengguan is to be revealed via the aspect that twelve Nidānas complete the “Pratītyasamutpāda of one mind”.
