The worship of mountain or mountain gods is popular in ancient East Asia, and blended with Buddhism in different ways. In China, mountain gods played an very important role in Daoism, while mountain gods in Korean peninsula coexisted with Buddhism. In Japan mountain gods were even assimilated into Buddhist system, becoming the pioneer of syncretism of Buddhism and godsworship. By inspecting Buddhist rites, different models of interacting relations between mountain gods and Buddhism can be discovered. Also, “Shanwang 山王” (Sannō), that is, King of mountain can be found in Buddhism related texts. Noticing these Shanwang in East Asian Buddhism, this paper will focus on Zhiyi’s “Jinglifa 敬禮法,” through illustrating Zhiyi’s creative view of seeing Shanwang (king of mountain) as Dharma-protecting god, and comparing with Saicho’s Sanbuchōkōeshiki, indicate the roles that king of mountain played in East Asian Buddhism.