The mandala which represents the mysterious level of achievement in religious practice with complex diagrams is the assembly of mystery and symbolism. What is the concept that mandala would like to deliver after all? Generally speaking, mandala contains the conception of cosmic pattern. By means of investigating the development of history, instruction of practice, analyzing of structure, and objects, etc., it is able to realize various internal and external phenomenon of mandala. Afterwards, we would gain the implication that most of the mandalas are collectively expressing. As to the methodology here in the thesis, not only the accomplishment of the literature about Buddhist Esoterism and theory of mandala-practice is inherited, but also the viewpoint of the study of religion is applied as well to search the basement of various elements of mandala. In order to achieve the exploration, it is not possible for lacking the united effort of iconography. Through the investigation of the development of history of mandala in chapter one, and the analysis of structure in chapter two, there something comes to us that taking the "enlightenment" as the center would be the fundamental principle of mandala. At last, the chapter three, by the means of realizing all the aspects about the fundamental principle, the essence of enlightenment, that mandala derives from, and basing on the understanding, we intend to interpret the mysterious solid mandala, Borobudur. Facing the strange form that Borubudur presents, scholars suggest various hypothesis by diametrically different approaches. In this thesis, it is thought, returning to the facts that the monument presents and hold them as clues, would be the foundation to lead us to achieve the reasonable ratiocination. By investigating the background, the monument Borobudur is related to Gandavyuha-sutra and main sutras of Yoga-tantra. As a clue, this conclusion suggests the monument is closely relevant to the Buddhist thought widely spreading in the time of Pala dynasty that located in eastern India. On the identification of buddha statues in Borobudur, the 72 buddhas in Dharma-cakra mudra on the three round terraces convey the central personality , Vairocana, who is described in Tattvasamgraha . As to the buddhas having Vitarka mudra on the fifth balustrade would be Sambhogakaya of Sakyamuni who has his first sermon at Akanistha as described in Avatamsaka. Further, the buddha who shows the demeanor of "Victory over Mara" with Bhumisparsa mudra was flourishing in Pala dynasty in eastern India. On the viewpoint of the inheritance of the thought and architectural design, it would certainly bring Borobudur some effects, so that, the buddha in the great stupa with Bhumisparsa mudra may be possibly the buddha in the demeanor of "Victory over Mara". The image of "Victory over Mara" is imitating from the moment of Sakyamuni''s enlightenment at Bodhgaya, and that means quite much to the doctrines in Avatamsaka and Yoga-tantra; for they''re both deducing their doctrines basing o
