現今社會因醫療技術的進步、生活水準的提高，讓人的壽命延長，又因近年來生育率的下降，讓世界許多國家面臨人口老化、勞動力不足等困境，亦會衍生出像扶養比、老年經濟安全等眾多問題，而台灣亦為高齡化國家之一，為確保國人退休後有完善的老年生活品質，考驗著政府該如何對退休金制度與年金制度做出適當的改革政策。而其中影響最大的就屬年金差額的部分，這同時影響被保險人在退休後請領A、B式年金給付時，造成被保險人退休金上的損失及政府在年金差額逐年增長的情況下，導致政府財務缺口隨之擴大的兩個面向。 因此本研究透過相關的情境假設及數據分析，探討國民年金制度中年金差額分別對被保險人及政府的影響，主要研究目的如下： 一、探討國民年金現況所面臨的問題。 二、國民年金老年年金A式給付的年金差額狀況。 三、國民年金老年給付A式給付落日的必要性。 四、站在被保險人的角度分析所繳保險費與領取老年年金中間的關係。 五、站在政府的角度來分析年金差額所產生的財務缺口。 最後本文會針對目前市場上老年年金制度所需要改變的地方，並從中提出對被保險人及政府兩者規劃方向的建議以因應未來之實踐。 With advancements of medical technologies in the society today, people have upgraded their living standards with extended lifespan; and, with decreased birth rates in the recent years, many countries are facing challenges in an aging population and lack of labor force, generating significant issues pertaining to the changing dependence ratio and financial security for seniors. Taiwan is one of those countries experiencing an aging population. To ensure seniors to have a complete and quality life after retirement, the government is facing a test in formulating a proper reform measure for its retirement system and annuity system. The major impact is the differentials in annuities, which may affect the insured to suffer losses on his/her applicantion while applying to receive annuity payments Type A or B, and with the government’s gradual increases in annuity gap, causing the government to enlarge its bi-directional financial shortfall. Therefore, this study is conducted under relevant hypothetical circumstances and data analyses, to probe on the differentials between the annuities and its respective impact on individuals and the government. The primary purpose for the study is as follows： 1.Probe on issues faced by the current National Annuity System. 2.Conditions of annuity differentials between payments of the Old-age Pension types A . 3.Mandatory conclusion of type A payment of the old-age pension. 4.Analyze the relationship between the premium paid and old age pension collection in regards to the insured''s view. 5.Analysis from the government’s perspective pertaining to the financial shortfall generated from the annuity differentials. In conclusion, recommendations will be provided regarding modifications needed of the old-age pension policies in the current market, and the respective planning direction from the insured and the government’s perspectives in order to meet future implementation.