This article attempts to explore the evolution of power structure of the two main parties in Taiwan and the possibility of transformation of party politics from divergence to convergence. Institutionally, the game of plurality voting system tends to marginalize the third party and encourage a balanced two-party system. It may also pull the two parties toward the central line amid increasing interparty competition. From the social perspective, however, the inherently different supporters of the two parties tend to pull the parties away from the direction of convergence. While KMT supporters are more caring about economic growth and a good relationship with the mainland, DPP supporters are more concerned about distributional justice and worried that close cross-strait relations may present a greater threat to the island, either politically or economically. These social cleavages have underscored different policy positions of the two parties. This article concludes that while the KMT and the DPP have reduced their difference in social and economic policies, they are still divided on the issue of how to deal with the Chinese mainland, namely, whether Taiwan should be attached to or detached from the mainland in the future.