The initiation of a Buddhist sect is one of the most important issues of Korean Buddhist history studies. Kim Young-soo has asserted that there were five Buddhist sects existed during Silla peirod. Even though his opinion has been widely criticised, the fact that the Avatamska Sect of Silla Buddhism can surely be characterized as a religious sect still remains reliable. This study concerns Uisang's foundation of the Avatamska Sect of Silla Buddhism and its development afterwards. The inheritance of academical tradition among Uisang's disciples, constructions of the Avatamska temples, and doctrinal arguments between Avatamska and Vijnapti-matrata scholar monks have been examined during the researching process. Uisang established Buseok Temple on Mt. Taebaek in the 16th year of the King Munmu's reign and started to preach the Avatamska study. This fact proves that the Avatamska Sect of Silla Buddhism was initiated by Uisang. His nickname, the very first originator of the Avatamska Sect of Korea, reflects the fact. Uisang had many disciples and ten of them, 'the ten great disciples', were especially noted. Jinjeong, Sangwon, Yangwon, and Pyohun are the representative ones and they were called 'the four geniuses' at the time. Uisang had handed down the Avatamska tradition to his disciples, and their successors all inherited the tradition from their masters. There were ten Buddhist temples built by Uisang and his disciples and they were called 'the ten Avatamska temples'. The inheritance of the Avatamska tradition and the construction of those temples were based on the factional consciousness of the Avatamska Sect. From the late 7th century to early 8th century, there were doctrinal arguments and conflicts between Avatamska and Vijnapti-matrata scholar monks. There are one legend about a Vijnapti-matrata scholar monk named Sungyeong from Silla which contains a story about him being turned into hell, naraka, alive since he criticised the Avatamska Sutra. This legend must have been derived from the difference between Avatamska and Vijnapti-matrata Buddhism. There were other arguments between the Yogacara and Avatamska Sects, Uisang and Uijeok, and Sungeop and Dojeung. These arguments and conflicts were likely to be initiated by their factional consciousness at the time. In the late 9th century, the Avatamska Sect of Silla Buddhism established the Avatamska Association to praise the achievement of their originators and to repay the originators' blessing. The Association was aiming to reorganize the Avatamska Sect for a new phase of their religion and to promote harmony in their sect. There is an inscription on the Iron Buddhist statue of Samhwa Temple and the term '華嚴業 ' is seen from the inscription. This term can be regarded as a specific evidence of the existence of the Avatamska Sect of Silla Buddhism.