本文討論焦點在於台灣政黨體系的變遷過程，影響台灣政黨體系變遷的因素，以及台灣政黨體系未來的可能走向。分別使用社會分歧理論、政治菁英理論以及制度論來解釋台灣政黨體系的變遷過程，並由各政黨在選舉結果的消長與選民政黨認同的變化兩個指標來觀察我國政黨體系的變遷。試圖建構一個通用的模式來解釋我國政黨體系發展的過程，以預期台灣政黨體系發展的未來走向。 經過全面觀察各政黨選舉結果的消長，以及選民政黨認同的變動情形之後，本文發現台灣政黨體系的變遷，主要發生在四個重要的時間點，第一個時間點是1986年民進黨的成立，第二個時間點是1993年新黨的成立，第三個時間點是2000年親民黨的成立與2001年台聯的成立，第四個時間點則是立委選制改變後的2008年立委選舉。 在變動的因素方面，雖然每一個變遷的時間點都有新政黨的出現，但是民進黨的出現是整個憲政環境由威權時期轉成民主化的結果，而新黨、親民黨與台聯則都是政治菁英之間的分裂。2008年主要是選舉制度的影響，不但新成立的政黨無法生存，連原有的小黨也都消失無蹤。 在穩定不變的因素方面，在台灣的政黨體系整個變遷的過程裡面，藍綠的區分一直都存在著。在藍綠對抗的主軸之下，台灣的政黨體系受到省籍、統獨立場以及國家認同等因素混合在內的分歧結構的長期影響，泛綠基本上掌握三成左右的基本盤，泛藍則是有四成出頭的支持度，中間還有二成多搖擺不定的部分，這個部分就是藍綠角逐的關鍵所在。這個藍綠對抗中第一個最重要的因素就是混雜了統獨立場、國家認同與省籍在內的社會與議題分歧，其次是政治菁英在歷次選舉過程中不斷地去操作這個分歧結構，藉此找到新政黨在意識型態光譜上的定位點，再加上SNTV選制容許小黨有生存空間，因此台灣的政黨體系隨之產生變遷。最後到了2008年，選舉制度的變革發揮了決定性的影響，使得我國的政黨體系確立為兩黨制。 在未來的發展趨勢上，研究發現，無論就政黨得票率、政黨支持度以及選舉制度的層面來看，國民黨似乎已經逐漸取回過半的優勢，民進黨則回到四成左右的基本盤。在沒有新議題或是新的政治社會分歧足以重新切割現有政黨體系之下，在目前雙首長制的憲政架構以及單一選區兩票制的國會選舉制度之下，我們預期政治菁英們的互動將朝向由國民黨代表泛藍勢力，民進黨代表泛綠勢力的兩黨政治體系逐步鞏固的方向前進。 / The main theme of this thesis focuses on the changing process of Taiwan’s party system, the factors which effecting the changing process of Taiwan’s party system, and the trend of Taiwan’s party system in the future. The author use social cleavage theory、political elite theory and institutional theory to explain the changing process of Taiwan’s party system. The author also uses two indexes including the vote-share of each party in every election, and the changing of voter’s party identification to observe the changing of Taiwan’s party system. This thesis tries to build a general model to explain the developing process of Taiwan’s party system and predict the future trend of Taiwan’s party system. After observing the election outcomes of each party and the changing of voter’s party identification, this thesis points out four important time points of Taiwan’s party system changing. The first time point is the presence of DPP in 1986, the second time point is the presence of NP in 1993, the third time point is the presence of PFP in 2000 and the presence of TSU in 2001, the fourth time point is the changing of electoral rule of legislative election in 2008. About the changing factor, in spite of the new party presence in each changing time point, the presence of DPP is due to the constitutional environment which the authoritarian regime transferred into democracy. The presence of NP、PFP and TSU are the outcome of the separation of political elites. The changing of party system in 2008 is mainly effected by electoral system, not only the new parties can’t survive, but the existing small parties also disappear. About the stable factor, during the changing process of Taiwan’s party system, there’s always a clearly distinction between “blue” and ”green”. Underneath the main stream of the confrontation between “blue” and “green”, Taiwan’s party system has long been effected by the cleavage structure which mixed with ethnic origin、unification or independent with china and national identity. The pan-green group basically maintains about 30% of vote share, the pan-blue group has more than 40% of vote share, the remaining 20% more of vote share is the key point for the struggle of pan-green and pan-blue forces. The most important factor in this confrontation process is the social and issue cleavage mixed with ethnic origin、unification or independent with china and national identity. Meanwhile the political elites are consequently manipulating the cleavage structure in every election process, in order to find some spaces in the ideological spectrum to form new parties. In addition to the SNTV electoral system allows small parties to appear and survive. That’s the reason why Taiwan’s party system changes over time. But in 2008, the changing of electoral system has the decisive influence and turn Taiwan’s party system into the two-party system. In the trend of future development, the research shows that, no matter in party’s vote share、party support rate or electoral system, KMT seems gradually having a leading advantage to get more than 50% of vote share. DPP has about 40% of vote share. If no more new issue or political-social cleavages to cut the existing party system, in the two-head executive constitutional structure and MMM electoral system, the interactions of political elites will tend to a consolidation of the two-party system which including a pan-blue force presented by KMT, and a pan-green force presented by DPP.