This study covered the features and development process of the stylobate of the Sumijwa style, which emerged in Silla around the late 7th century. In the Period of North and South Dynasties, Sumijwa was used as the seat of the Buddha. It was used as a stylobate of tower in the Sui Dynasty and as a stylobate of central buildings in the Tang Dynasty, raising the status of buildings. In the late 7th century, Silla faithfully embodied Buddhist view of the world under its architecture by accepting the latest stylobate of the Sumijwa style. The pagoda of Hwangnyongsa Temple is believed to be the beginning of the stylobate of the Sumijwa style, in Silla. Gradually, in the central buildings within the capital, the stylobate of the Sumijwa style became common. Starting with Bulguksa Temple's Daeungjeon Hall, the materials of stylobate and staircaes will be integrated from the late 8th century. Silla's stylobate of the Sumijwa style can be evaluated as a step-by-step leap in religious, political, technical and aesthetic's terms.

This study aims to classify the architectural formation of the Stylobate of and Staircase types of Post-Lintel Construction in Backje style and Silla style and also to figure out their specific elements by periods and transformation characteristics. The scope of this study was restricted to architectural remains between the Three Kingdom period and the Goryeo period. To progress the investigation, the study classified remains in a similar type by period and type, and then and analyzed its character based on formation method and specific factors of subsidiary materials. As a result, its type can be classified as Backje type(Ⅰ), Silla type(Ⅱ) and Mixed type(Ⅲ). Regionally, it is found that Woongjin, Sabi and surroundings in the capital of Backje, Gyeongju and main towns in the capital of Silla, and Gaeseong and main towns in the capital of Goryeo. In particular, type III has the characteristics of type I and II simultaneously, which has one or two layers Jangdaeseok stone between the foundation stone of stylobate and plate stone, and tends to be decorative when Taengjuseok stone is installed. For types of staircase, it could be classified as 6~7C Backje type(Ⅰ), 7~9C Silla type(Ⅱ) and 9C Mixed type(Ⅲ) according to the formation method of Somaetdol (banister of stone stair). And from the 9th century on, decorated Somaetdol stone type(IV) of 1/4 circle shape began to appear. The common feature of stylobate of post-lintel and staircase is that it became simplified, abbreviated and decorative. It seems to be intended to secure simplicity of construction or structural stability.