Based on the related canons of the northward- and southward-spreading Buddhism，the collection of `agamas` during different Councils and the origion of the `Mahayana` `sutras` are studied.
It is pointed out that (1) the initial format of Samyukta and Ekottara has been used by Shakyamuni Buddha in teaching Dharma. (2) At Buddha's middle and old ages, the Buddha concluded the teachings as nine or twelve branches of scripture which include Vast Texts (Vaipulya). (3) In the first Council at Rajagrha, the set of `sutra` are collected in the order of Samyukta, Madhyama, Dirgha and Ekottara `agamas`，then the set of vinaya are collected. The content of the set of `sutra` is limited to the topics of aggregates, sources, dependent arising and so forth, whereas the Vast Texts are not included due to their large volume and different purpose. (4) In the second Council at Vaisali，the set of vinaya are collected first，then the set of `sutra` are collected in the order of Dirgha, Madhyama, Samyukta, Ekottara and Ksudraka `agamas`. (5)After the second Council，sanghas are divided into Four Saint Groups (Sthaviravadinas, Mahasamghikas, Vatsiputriyas, Sarvastivadinas) due to the debate of the meaning of the Dharma and the impact of the philosophy of Vast Texts. The set of abhidharma are collected by the sthaviras of Vatsiputriyas 200 years after the Nirvana of the Buddha. (6) In the Council at Pataliputra, the set of vinaya, `sutra` and abhidharma are collected in succession，whereas the set of `sutra` is collected in the order of Dirgha, Madhyama, Samyukta, Ekottara and Ksudraka `agamas`. The internal orders of the `sutra` in each `agamas` are rearranged，the overlapping parts of the `sutras` among different `agamas` are eliminated，and the sentences in the set of `sutra` are adjusted so that they are consistent with those of the vinaya as recited by Upali. (7) Because of the influence of the Councils and the difference of lineages, seen different orders of `agamas` are formed. We note that the school of Sarvastivadinas is not a branch of the Sthaviravadinas of the Vaisali Council. (8) The essential parts of the `agamas` and the `Mahayana` Vast Texts are the words spoken by the Buddha or agreed by the Buddha.
In this paper，related scriptures are quoted successively support the above statements.
