This paper argues that the establishment of legislator professional ethnics is the key to the success of the Legislative Yuan reform. In recent years, parliamentary reform has been the focus of democrazation and became one of the main election campaign issues in Taiwan as well. In general, the inefficiency and chaos of the Legislative Yuan was blamed upon the legislators, particular the number of the parliamentary seats. In order to improve the function of the Legislative Yuan, some suggested that the seats numbers should be reduced from 225 to 150, and extended the three-year tenure to four years to coincide with the presidential tenure, and also replaced the small electorates with multiple seats to single-seat electorates with proportional representation. However, will these efforts make the reform success? Beside the institution reforms, in my point of view, another critical aspect is: how do the legislators cultivate that profession ethics and expertise? Therefore, this paper stresses that only both outer and inner force reform, such as constitution structure, electoral system, media supervision, professional ethics, would then make the Legislative Yuan reform work, not only improving the role of the legislators but also the function of the Legislative Yuen.