立法院常設委員會乃法案審查之最重要機制，而立法委員在審查法案過程中可能直接或間接影響立法結果，因此，立委在常設委員會審查法案的各種立法行爲便顯得十分重要。 本文旨在研究立法委員於常設委員會審查法案時的五種主要立法行爲，包括：連署、發言、保留院會發言權、參與協商及提出法案，並深入探討立委在審查委員會上的發言內容是否受到政黨、選區、個人及國會制度等因素的影響。 本研究以「公共事務類」法案－「公共電視法」與「國防法」進行個案分析，經過實際檢證，研究結果有三：第一，立法委員的行爲並非只受單一因素影響，而是許多因素相互競逐；第二，法案的發動機關不同，會衍生法案通過與否的變數；第三，立委的立法行爲未必符合影響因素的行爲假設。

"Standing committees" are the most important investigative mechanisms in the Legislative Yuan. Legislators are in charge of creating legislation and they are responsible to the entire population of the country. Legislators’ behavior may directly or indirectly affect the legislative process and outcomes. Among the legislators' activities, the investigation of bills in the standing committees is the most significant. Therefore, the main purpose of this thesis is to focuses on legislator's behavior in investigating bills in the standing committees. The behaviors examined in this study include petition, speech, reserving the right to speak in the chamber, and negotiating and addressing bills. I will analyze the content of legislators' statements in the standing committees. According to the "theory of representation," members will represent whatever affects them the most. This study conducts a case study analysis of the Public Affairs Bill, which included the PTS Law and National Defense Law. Empirical testing suggests three conclusions. First, a legislator's behavior is not only affected by a single factor but also by other factors. Second, the authority which introduces a bill is a variable affecting whether a bill passes or not. Third, the Legislative Yuan lacks professionalism and is pervaded with opportunism.