本文探討我國公共債務法和國際貨幣基金對債務的定義有何差異，並依照國際貨幣基金的定義編算我國政府總債務餘額。結果顯示99年各級政府總債務餘額為6兆8032億元，佔GDP比例為50％。與財政部公布的5兆1893億元，佔GDP為38.1％，確實存在一定的差距。再者採用簡單的線性迴歸，推估我國債務餘額佔GDP比例在民國115年會達到58.3百分比至84.9百分比之間，145年將達到66.2百分比至135.8百分比之間，160年達到68.4百分比至157.5百分比之間。目前資料顯示，債務佔GDP的比例和利息支出佔GDP的比例兩者都較其他先進國家低，但稅收佔GDP的比例在2009年卻低到12％，顯示未來償債的能力有不足的疑慮。 This paper compares the definitions of public debt between Taiwan Public Debt Act and International Monetary Foundation (IMF), and calculates the total Taiwan public debt in terms of the IMF definition. We find that total public debt is 6803.2 billion NT dollars in 2010 which reaches 50% of GDP. However, Ministry of Finance announces that public debt is only 5189.3 billion and 38.1% of GDP. Moreover, we use a simple regression model to forecast the debt-to-GDP ratio, and find that the range of this ratio is between 58.3% and 84.9% in 2026, between 66.2% and 135.8% in 2056, and between 68.4% and 157.5% in 2071, respectively. So far, both Taiwan debt-to-GDP and interest-payment-to-GDP ratio are lower than advanced countries but tax-revenue-to-GDP ratio is only 12% in 2009, which calls future debt-paying ability in question.