A few archeological excavation of Buddhist temple sites of Koguryo were reported with information of site arrangement. The interpretation of such information is very important not only for the explanation of Korea early Buddhist architecture but also for the development of East Asian cases in general since no archeological evidences of the same period were found in other countries such as China. Though the investigation of the four temple sites this paper attempt to identify their date of construction and the process of change. The study depended much on comparative studies of the change of site elements such as pagoda, image hall., corridor, and other buildings. The study could conclude that the site of SangO-Ri must be the earliest case which was followed by ChungRung-Sa, which was built in around 427AD. The site of ToSung-Ri was the case which was the work of the rate 5th century. Such process of the development of Buddhist architecture in Koguryo unveils the fact that the process of change was a continuous flow toward a consistent goal of change that had much to do with the contemporary religious situation.