InwangDoryang(仁王道場) was originally derived from InwangSutra(仁王經), which made a triad for the national defence of Beobhwa Gyeong(法華經) and GeumgwangmyungGyeong(金光明經). InwangDoryang(仁王道場) occupied the most pivotal places in Koryo˘ Dynasty and was held in great account. The national buddhist ritual of Koryo˘ Dynasty`s essentials are the state protective and invoking a blessing, keeping off a calamity. InwangDoryang(仁王道場) was originally derived from InwangSutra(仁王經), which made a triad for the national defence, had an old and new version. During Shilla(新羅) period. The old version was flouirshed, during Koryo˘ dynasty the new version bulgong(不空). Especially the exchange between Daegakguksa(大覺國師) Uicho˘n(義天) and Jungwon(淨源) of Song(宋)Dynasty`s InwangSutra(仁王經) notes are the basis of the new version of bulgong(不空). InwangDoryang(仁王道場) in the middle of Koryo˘ Dynasty was performed 20 times at the time of King Munjong(文宗)-Sukjong(肅宗). They were held on the purpose of corresponding to the nation and the social issues Uicho˘n(義天) accepted a new idea, a measure to strengthen the country the Sung(宋) Whaumjong(華嚴宗) preist jungwon(淨源) connected with the new law party(新法黨). In fact, his new ideas shed light on the controversy the mintage(鑄錢論) in the middle of Koryo˘ Dynasty at the time of King Sukjong(肅宗). Following this point, Uicho˘n(義天) had an intention to make a drastic reform of the high lineage aristocracy, at the same time he would like to strengthen royal authority. Uicho˘n(義天) political reform and The InwangSutra(仁王經) belief were closely associated with one another. Examples are as follows-① the road ahead upholding of InwangSutra(仁王經), ② performing InwangDoryang(仁王道場) rituals 20 times, ③ The InwangSutra(仁王經) and its notes(注ㆍ疏) in the Tripitaka in the early Koryo˘ Dynasty and Sinpyonjejonggyojangchonglok(新編諸宗敎藏總錄) and so on. They are of a concrete revealation of InwangSutra(仁王經) belief of in the Middle Koryo˘ Dynasty, and a strengthening measure for royal authority. During the exchange between Uicho˘n(義天) and Jungwon(淨源) connected with Sung(宋)`s new law party(新法黨), Uicho˘n(義天) was affected Jungwon(淨源)`s new idea and was accomodating to InwangSutra(仁王經) belief. As it shows. Uicho˘(義天)`s realization of Inwangdoryang(仁王道場)-Inwang baikgojwa beobhoe(仁王百高座法會) - is a regular rituals to be held once every three years, be given to banseung(飯僧), large scale continuance national buddism ritual at the same time. Due to the contents of InwangSutra(仁王經) which state superiority of the king and defense-country`s application of the law, it can be recognized centralization of government`s interpretation.