Administrative plan, in more specific stated as Administrative Plan Law, is an important topic in Administrative Laws. It's also an important issue in the of Administrative Act. The transportation plan, which affects the allocation of national resources and peoples' lives, is one of the most important administrative plans. After more than 20 years, progressive improvements on transportation planning techniques of demand forecast and evaluation analysis have been achieved since “ The First Taiwan Area Integrated Transportation Systems Planning Study＂ in 1976. However, transportation plans, the products of transportation planning study which often concern lives and interests of people, are occasionally affected by the politics. Moreover, the proper process of planning has not been followed in several agencies, and the results form these planning process might mislead the alin ocation of national resources. To promote the efficiency of national transportation system investment and the benefits of people, it is necessary to establish an institution that legalizes the transportation planning process as well as its contents and decision making process This article reviews related literature and analyzes the characters of transportation planning， investigates the problems of the legitimization on administration law in Taiwan and details a proposed contents for the Integrated Transportation Law. Weexpect the proposed process can strengthen the Law of Administrative Procedural in transportation planning.