Various studies have been undertaken about Ryouou. Some, who focus on mask, argue that Ryouou was originated India. However, the existing view of its introduction from China is found to be more compelling when examining Kyoukunshou(敎訓抄) and other literature records. Meanwhile, performance records in Bugakuyouroku(舞楽要錄) was analyzed to study the image of Ryouou. Among the five main events recorded in Bugakuryoroku including the grand Buddhist meeting, Hakkou(八講), Tyoukingyoukou(朝覲行幸), Onga(御賀), and Sumaisechie(相撲節), it was found that Ryouou was performed most frequently in the first four events excluding Sumaisechie. In addition, it was found that Ryouou was most frequently performed followed by other music pieces such as Manzairaku(万歲楽), Sanju(散手), Daiheiraku(太平楽), Sokou(蘇合香) and Shunnoten(春鶯囀) followed Ryouou in performance frequency. What is noteworthy is that these music commonly praised, prayed and celebrated the exemplary rule of the emperor or the king and symbolically expressed the authority and dignity of the imperial family. Then, how was Ryouou perceived in Japan? Ryouou was not so different from the aforementioned music. As the motif of a hero in an turbulent era was added with the image of a dragon, it is concluded that Ryouou was perceived in Japan as a music that represent a combination of the dignity the congratulatory message, prayer for the imperial family, and the peaceful regime of the king.