Previous studies on architecture during the Japanese colonial period have generally assumed that it had colonial characteristics. This conceals the various aspects and reveals limitations in illuminating its diversity. In this context, Daejojeon and Heejeongdang are very valuable cases that allow us to examine the process by which Western modern images were accepted into our traditional spaces. This study examined the architectural background of the eclecticism of Korean and Western styles in traditional palaces during the Japanese colonial period, and analyzed the characteristics of Korean-Western blended interiors that appeared in the interior façades of Daejojeon and Huijeongdang in Changdeokgung Palace. Attempts of construct façades by blending different styles within a single room starting from the Japanese colonial period, and the background of this was the influence of Japan, which experienced the eclecticism of Japanese and Western styles.To summarize the Korean-Western blended aspects that appeared in the façades of Daejojeon and Huijeongdang, they were created by adding Western-style finishing materials and decorations to the proportions of the façades of traditional palace. Korean traditional elements were concentrated on the upper part, and Western elements were concentrated on the lower part, and the integration between the two styles was combined through lintels and dado. Decorations and finishing materials were used as elements expressing the hierarchy of room, and they have decorative characteristics that appear in the French style of the 17th and 18th centuries. The interior façade shown in Daejojeon and Huijeongdang were introduced in the special political and administrative situation of colonial rule, so it is limited to viewing them as a true expression of modernity. However, they provide many implications for understanding the domestic perception and sensibility of Western interior decoration at the time, and the status of the domestic interior design industry.