Recognizing that the debate on the original form of the Seokguram Grotto is closely related to the mythologization of the Seokguram Grotto, which is far from factual understanding, this paper is prepared to restore the Seokguram Grotto based on scientific facts. To this end, we will first analyze its active meaning and fiction from three directions: the founding legend, the rediscovery story, and the concept and discourse of the Line of sight for Buddha statue (對佛像視準線), which have contributed to the mythologization of the Seokguram Grotto. The original restoration of the Seokguram Grotto should be based on a scientific understanding of the Seokguram space. However, past debates and restoration attempts have been based on imagination and not on scientific knowledge. Therefore, Chapter 3 attempts a scientific analysis of the light environment of thr Seokguram Grotto and critically examines the existing errors and realistic mythological images to correct the public's spatial perception of Seokguram's architecture and to propose a rational restoration of Seokguram's architectural space.