最近，我國正掀起一股老年年金的熱潮，為了對這個議題提出一些意見，筆者試圖從經濟模型去探討公共老年年金保險的財務理論及其對國民經濟的影響。本文分為五節，第一節是在介紹老年年金保險的財務方式與給付水準；第二節是在說明隨收隨付方式與累積基金方式的保費計算模型；第三節是在比較隨收隨付方式與累積基金方式的保費負擔與社會效用；第四節是在分析老年年金保險對國人儲蓄、社會儲蓄、投資行為、勞力供給等國民經濟的影響；最後一節除了推論老年年金保險將對國民經濟產生正面影響之外，也建議政府宜採累積基金方式作為國民年金保險的財務制度。

　　　　　Recently, old-age pension has been becoming a hot social issue in this country. In order to contribute some opinions to this issue, I tried to discuss basic financial theories and some economic impacts of public old-age pension insurance (POAPI) through economic models. This paper includes five paragraphs. The first paragraph introduces financial methods and payment level of POAPI. The second paragraph illustrates premium calculation methods of pay-as-you-go system and reserved funding system. The third paragraph compares premium burden and social utility of pay-as-you-go system and reserved funding system. The fourth paragraph analysis some economic impacts of POAPI including personal saving, social saving, investment behavior as well as labor supply. The final paragraph concludes that POPAI will have positive impacts to national economy and suggests that the government has better to adopt reserved funding system as the financial method of National Pension Insurance System.