The trends of historical studies of North Korea have changed from simple introduction to analysis and comparison and then to critical evaluation in South Korea. Since the late 1980s, the interest in the historical studies of North Korea increased influenced by the academic movement for promoting understanding of the North Korean society and preparation work for reunification. The atmosphere continued until the 1990s, but it turned around since 2000s. It was probably because that it was difficult to discover anything new from the historical studies of North Korea which were stagnant and regressing. One of the things South Korean scholars can do apart from verifying and criticizing the differences of North and South Korean historical studies is to reaffirm the homogeneity between two Koreas. By identifying the homogeneity, North and South Korea may find a lot more commonalities in various areas. In fact, North-South historical exchange which first took place in the beginning of 2000s had expanded based on the consensus on the homogeneity between the two Koreas. Promoting mutual exchange is a realistic and inevitable option for co-existence of North and South Korea.