大多數民主國家的國會議員都必須扮演兩個角色，一方面他是由各自選區選出的代表，另一方面他又是整體國會組成的一份子。前一個角色促使他必須作選區民眾意見與利益的代言人；而後一個角色促使他必須站在國家整體立場，為整體利益來立法與決策。本文的主要目的是探討我國立法委員如何扮演此二角色，並且瞭解一般民眾對於立法委員角色的期待以及其對立委實際表現的評估。研究結果發現，相當多的立委著重選區代表的角色，面對選區利益與國家整體利益相違的時候，立委往往站在選區的立場，極少扮演國家整體利益受託者的角色來衛護國家整體的利益，立委此一角色的扮演事實上與大多數民眾所期待的代表圖像有一段落差。造成立委傾向選區的主要原因有四：立委連任的考量、立委在立法與決策上的無力、有限資源的爭逐、以及政黨的惡性競爭。

Legislators in most democratic countries have to play two roles: one is a representative of their constituencies, and the other is a member of the whole legislature. The former role pushes them to be delegates, who listen carefully to constituents and articulate opinions and interests of constituents; while the latter role pushes them to be trustees, who make laws and policies in behalf of the interests of the whole country. This article explores how Taiwanese legislators play these two roles and what Taiwanese expect from their legislators. The research findings show: Most legislators put much more weight on the role of the constituency representative than on that of the collective representative. Whenever legislators face contradict between the special interests of their constituents and the collective interests of the whole country, most legislators play the role of delegate to protect the interests of their constituents. There is a wide gap between the expectations of the public and the actual role-playing of the legislators. Further to this, research findings show that legislators’ role-playing is associated with legislators’ pursuit of re-election and their incapability in law-making, the distribution of scarce resources, and the inferiority of party competition.