Christianity has been a very important subject in Mongolian Studies. This branch isinformed both by classic books on Christianity in the Mongol Empire by eminentscholars, such as Yoshiro Saeki and Namio Egami, and also by several recentarchaeological works. However, in these studies the influence of Christianity inMongolia has been discussed separately in terms of different historical periods andregional divisions. And so the synchronic development and interaction betweenChristianity and Mongol Ethnic Identity have been left unexamined. This article aims toshow the importance of historical analysis on the continual interaction of ChristianityandMongol ethnic identity for the studies on Nationalism and Religion.