It is well known that the issue of unification has been affecting every branch of the Korean society from politics, to economy, and to culture and religion, including Christianity; and that the Korean Church has made concerted efforts to tackle this issue. However, the Korean Church still suffers from the paucity of full–fledged theological discussions, although inundated with diverse discourses on that issue. This article aims to review the development of ‘Tongil(Unification)Theology’ which has arisen since the 1980s, summarizing it into several patterns, and clarifying main themes. The patterns are as follows:first, the period approaching the issue from the perspective of national division(1980–1998); second, from that of exchange between South and North Korea(1998–2008); third, from that of integration(2008–present). This article makes it clear that the patterns of Tongil Theology in each period have different characteristics from various angles: first,the number of the parties concerned of unification varies from one,to two, and to three and more, namely, from a unilateral, to bilateral,and to multi–lateral model; second, the emphasis of the historical aspects shifts from past, to present, and to future; third, the most interested area fluctuates from politics, to economy, and to culture;and last, outstanding theological pattern alters from Theology overcoming national division and Jubilee Theology, to various discussions over ecclesiology and missiology, Tongil Theology, Peace Theology, Reconciliation Theology and Theology of Diaconia, and to Integration Theology and Theology of Christian Socialism.