隨著老年人口比例日益提高，但是新生兒愈來愈少之情況下，將導致老年人口未來扶養比率嚴重不足之問題產生。國民年金概念自1992年立委大選中被提出，發展至今已通過行政院之審議，並在2007年7月完成立法程序。該制度在規劃上主要由經建會及內政部負責規劃，政策規劃成果共計有「儲金制」、「稅收制」及現階段〈國民年金法草案（社保制）〉三個主要不同的規劃方案。 本研究應用W. Dunn之政策論證模式中之「價值批判」與「因果解釋」途徑來針對不同版本間之〈國民年金法草案〉，進行論證比較，以了解三版本之適宜性，以提供相關政策資訊。 在經由論證模式比較後，發現國民年金儲金制枉顧弱勢族群之權益，政治可行性較低；稅收制較具公平正義之特質，但易造成政府有失靈之虞；最後，現行〈國民年金法草案〉則是兼具前二者之長，較符合中庸之道，但缺乏強制力，則為該制度之重大缺陷。

The aged population ratio increased on Taiwan, but the neonatal population ratio reduced year by year. This situation may let aged-caring be an important policy issue in the future. In the legislator campaign in 1992, the claim of national pension has advocated for the first time. Up to now, the national pension has reached consensus in Executive Yuan and finished legitimization process in July, 2007. In process of policy planning, agencies of Council for Planning and Development and Ministry of the Interior have responsible for plan the National Pension Protocol. There are three alternatives for the initiation of National Pension System—“system of defined contribution”, “system of taxation”, “system of social insurance”. This article utilizes the modes of policy argumentative analysis developed by William Dunn to analyze the different alternatives of National Pension System. Especially the “value-critical mode”and “explanatory mode” of policy argument. And then to discuss the adaptability of three different alternatives. Through the comparative study and argumentative analysis, this article has three main findings. First, National Pension Protocol of defined contribution system is overleaping benefit of the disadvantaged minority, so the political feasibility will be a serious problem. Second, the system of taxation has the ethos of fair and justice, but the system of taxation is likely to raise the problem of government failure. At last, the system of social insurance have advantage of the others, therefore the system of social insurance is the “middle way” , but it’s drawback is a lack of compulsion.