Deoksugung Palace Art Museum was built in 1938 as the first professional art museum in Korea. In 2015, National Research Institute of Cultural Heritage published a book on architectural drawings of this building. This book, called Architectural Drawings of the Deoksugung Palace Art Museum, consists of 646 sheets, 23 types of documents, as well as other historical letters. This paper focuses on the analysis of the characteristics of classicism in Architectural Drawings. It shows that every dimensions of drawings were controled by 3 partition composition through the analysis of architectural plan drawings, elevation drawings and even section drawings. Thus, Classicism for the museum is not about classical elements but the principle of composition of each elements for the construction. This paper further argues that Deoksugung Palace Art Museum exemplifies beautiful Classicism architecture which follows the principle of classical architectural composition.