1. Meaning: Buddhism is the oldest of the three major religions in the world. As a branch of Buddhism introduced to the north, Korean Buddhism is an important member of the Buddhist cultural circle in East Asia. It originated in China and formed its own unique nationalized Buddhism. In history, it formed a two-way interactive exchange with China, which had a far-reaching impact on the spread and exchange of Buddhist culture in other neighboring East Asian countries. The Koryo period was the heyday, maturity and golden age of Buddhism on the Korean peninsula, and reached its peak and decline at the end of Koryo. And in the Koryo period, a unique Korean national Buddhism was formed, and it is still the largest main Sect of Korean Buddhism. Therefore, Buddhism in Korea is an important historical period in the history of Buddhism spreading to the north on the Korean peninsula, which is of great research value.

2. Objective: To study the historical internal and external factors of the transformation of Korean Buddhism from royal political Buddhism to religious nationalization, the characteristics of the existing form of Buddhism in Korea in this historical process and its evolution process, the main representative figures and events in this evolution process, and the social, political and economic systems that influenced and restricted it, so as to understand how Buddhism in this important historical period changed from royal political Buddhism to religious nationalization and folk.