A sharp contrast of landforms in Taiwan lures many people to investigate. The northern part of Taiwan has lots of flat plains such as Ilan Plain and Pingtung Plain, while the southern part of Taiwan is concentrated with many high mountains like Yushan reaching about 3950m. This huge difference in topography is the consequence of the flipping of subduction polarity. Most of models studying this phenomenon will focus on an active collision in Taiwan which appears to reveal the incipient stages of subduction reversal.