本文以歷史制度論為研究途徑探討台灣憲政體制的變遷過程，並將其變遷軌跡予以圖像化。自一九九○年代初以來，台灣憲政體制的變遷乃是受到修憲、大法官釋憲與實際憲政運作這三種動力的交替發生與互相牽引所促成。台灣憲政體制經由第一至三次修憲所造成的路徑依循，使得我國憲政體制自此被框限在「半總統制」的路徑上，並經由大法官釋憲的明確宣示，將我國憲政體制確立為半總統制的次類型—「總理總統制」。但是，第四修憲又將我國憲政體制轉為內涵不明的半總統制。在二○○○年台灣首次政黨輪替至今，此一原本內涵不眀的半總統制經由實際憲政運作而被操作成半總統制的另一次類型—「總統議會制」，而大法官釋憲亦屢次承認「總統議會制」的合憲性，使得「總統議會制」有逐漸確立之勢。整體看來，自台灣半總統制的憲政體制正式確立以來，曾經浮現過的「總理總統制」稍縱即逝，隨後便逐步走向「總統議會制」。展望未來，台灣的憲政體制最有可能的發展方向仍是流連於半總統制的路徑上，並繼續維持並鞏固目前的「總統議會制」，但仍不能完全排除轉向「總理總統制」的可能性。

This paper tries to explore the transition process of Taiwan’s constitutional system and visualize the transition course by the historical institutionalist approach. Since the 1990s, the transition of Taiwan’s constitutional system had been brought up by three powers, which are constitutional amendment, judicial review and constitutional practice. Due to the effect of path dependency resulting from the first three constitutional amendments from 1990 to 1994, Taiwan’s constitutional system was henceforth restricted in the path of semi-presidentialism. Moreover, through the judicial review made by the council of grand justices, Taiwan’s constitutional system was identified as premier-presidentialism, one sub-type of semi-presidentialism. However, the forth constitutional amendment in 1997 made Taiwan’s semi-presidentialism ambiguous. Nevertheless, the ambiguous situation did not last long. Since the year 2000, when Taiwan’s first party alternation in power took place, the constitutional practice had led the obscure semi-presidentialism into president-parliamentarism, another sub-type of semi-presidentialism, and the grand justices’ judicial review also repeatedly recognized the constitutionality of president-parliamentarism, the establishment of which seemed gradually evident. Overall, ever since Taiwan’s constitutional system was shaped as semi-presidentialism, it had been changed to premier-presidentialism, which had a fleeting existence. It was then on the way to president-parliamentarism. Looking into the future, the most probable direction that Taiwan’s constitutional system will go is still lingering in the path of semi-presidentialism, and the current president-parliamentarism system is continuing and consolidating. However, the possibility that it will return to premier-presidentialism shall not be completely excluded.