This thesis deals with construction method of affiliated staircases oftrial-excavated and excavated eupseongs(邑城s, town walls) in southcoastal region of Gyeongsangdo province in Josun dynasty, concentratingon transition process of the inner wall. Most of the eupseongs(邑城s) investigated in the southern coastal regionof Korea were constructed during Taejong dynasty and Yeonsan-gundynasty in Josun(朝鮮). Fortresses built around Sejong dynasty show theconstruction methods similar to those written in 「Chukseongsindo (築城新圖)」, published in 1438(20th year of King Sejong’s reign) and what LeeBoheum(李甫欽) supplemented in 1443(25th year of King Sejong’s reign),which means these methods became fundamental instruction in buildingeupseongs and jinseongs(鎭城s) in Josun dynasty. As presented in Lee Boheum’s supplement, he proposed applying const-ruction method of the capital walls to stonification of the eupseong walls. Even though some differences could be found in detailed constructionmethod, terraced afterfilling of the surface stone of the wall was found inHadong-eupseong and southern wall of the Barrack of GyeonsangjwadoProvince in Ulsan. Therefore, as shown in excavation results of eupseongs in the southerncoastal region of Gyeongsangdo province, inner walls of the provincialeupseongs are built in terraced stonework system based on 「Chukseong-sindo」 like the capital walls in Early Josun dynasty. Especially, terracedmasonry afterfilling, which fairly reflects the rules and forms of 「Chuk-seongsindo」, is found in excavation of Hap-poseong Site, Ungcheon-eupseong in Changwon, Sadeungseong Site in Geoje, which are bulit in King Sejong’s reign. Moreover, walls to which supplementary measuressuggested in 「Chukseongsindo」 are applied like Sacheon-eupseong havebeen investigated. Finally, it came out that structure of the inner walls arechanged from terraced masonry afterfilling to method in which one side isupright masonry and another is slantly filled soil and stone as shown insome eupseongs like southeast wall of Ungcheon-eupseong, which wasextended in 1453(1st year of King Danjong’s reign), Gohyeon-eupseongbuilt in 1451(1st year of King Munjong’s reign) and Eonyang-eupseong inUlsan built in 1500(6th year of Yeonsan-gun). Meanwhile, staircases arefound in Hadong-eupseong and Sadeungseong. In addition, wooden pillarsinstalled in moats was found in Ungcheon-eupseong and Gohyeonseong. The Masonry method of inner walls of the southern coastal fortresses ofGyeongsangdo province shows large alteration in the late Josun Dynasty:it changes to a method of filling soil and stones to some extent behind the surface stone wall instead of setting up foundation stones on the outer wall, which can be found in Dongnae-eupseong constructed in 1731(7thyear of King Yeongjo’s reign) and Tongyeongseong site constructed in1678(4th year of King Sukjong). Meanwhile, staircases connected to the upper side of the wall are found in Hadong-eupseong and Geoje Sadeung-seong site.