Xuanri Tongshu is an official calendar published by the Ryukyu Kingdom. It is based on Qing China's Shixian shu (state calendar of the time), while also taking into the elements of Ryukyu's own customs and traditions. Because many texts of the Ryukyu Kingdom have been lost after entering the modern era, not many copies of Xuanri Tongshu have been identified. The author of this paper recently found eight copies of this book, which haven't been identified before, in the collection of the former Governor-General of Korea, preserved today in the National Library of Korea. These newly found materials are of great value both to the research on Chinese texts in Ryukyu as well as to the research on Ryukyu calendrical books. Drawing from the preliminary research on current extant copies of Xuanri Tonhgshu and related historical materials, this paper first provided an overall history of calendrical books compilation in Ryukyu, then analyzed content of Xuanri Tongshu, together with its the relationship to Qing China's Shixian shu. Through these analysis, this paper shed light on the characteristics and importance of Xuanri Tongshu preserved in the collections in the National Library of Korea.