In the Gyeongju Seokguram grotto ere enshrined 40 Buddha statues. There have been a large number of discussions on their names, characters, and iconological characteristics, and such discussions have been particularly focused on the main Buddha statue. This study also purposed to examine the names and iconological characteristics of the main and attendant Buddha statues, centering on the main statue.This study, firstly, explored the philosophy of foundation through the Yuga School, and secondly, analyzed the main statue of Shakyamuni Buddha iconologically through the statues of Shakyamuni Buddha and the attendants.First, in the results of analyzing literature including Samgukyusa and newly published records on the restoration of the Shakyamuni Pagoda, it was found that the grotto of Mt. Toham had been operated continually by the Yuga School or the Yuga Esoteric Sect at least until the early Joseon Dynasty.Second, from the iconological analysis of Bodhisattva and attendant statues, the main Buddha statue and the attendants created based on the thought of the Yuga School or the Yuga Esoteric School were identified as Shakyamuni Buddha and his followers. In addition, the organic and vivid expression of the Buddha statues in the grotto as described in Tuoluonijijing (Dharani’s Collections of Sutra) confirmed that fact that they are the world’s greatest Buddha statues that carried out Jinhogukga (鎭護國家: protecting the nation through suppressing revolts) and the protection of the Buddha Land (佛國土).