During the Joseon Dynasty, the Yanggwan was a public official hat worn on uniforms, and there was a difference in the hierarchy of public officials according to the number of sheep (梁). This study aims to empirically examine the difference between the regulations of the Yanggwan system and the actual operation of the Joseon Dynasty. To this end, institutional changes were examined through literature, and the Yanggwan artifacts held at the Seoul Craft Museum were empirically analyzed. During the Joseon Dynasty, Yanggwan was stipulated as a uniform system for government officials, and it continued without any change in terms of the system until the late Joseon Dynasty. However, these institutional norms were adapted and implemented flexibly according to the circumstances of the time. In 1651, the standard for wearing a uniform was reduced to 'a uniform of 4 or more items and a black danryeong of 5 or fewer items', and the system was adjusted to meet political changes, such as expanding from 1 to 7 items during the Korean Empire. In addition, from the King Injo's era, the uniform officers and the uniform officers were classified, and this was used again after King Yeongjo, but the distinction was maintained in practice. As a result of analyzing Yanggwan's actual findings at the Seoul Craft Museum, Jo Bok-yong's 冠was identified as a unique form without spirits (梁柱) and was modified for practical use. The Geumgwan and jegwan were used to convey symbolism suitable for the purpose, with the phoenix and the Square Knot motif, respectively, and their identities were commonly revealed through the use of the Lotus motif. The material analysis of the blue corrosion observed on the Yanggwan suggests the Brass component, which was introduced during the Jungjong (中宗) era, might have been the primary gold pigment. In addition, the painting data confirmed the change in the way the Chin strap(纓) was worn, tied, or tied under the chin according to the times. This study provides basic data for understanding the changes in the Yanggwan system in the Joseon Dynasty, and suspended academic research can be expected through scientific analysis in the future.