目標：探討不同死因對高雄市和臺北市兩地居民平均餘命差距之量化分析，提供不同人口健康差異之研究方法。方法：利用衛生署及內政部提供之1981年至2001年之死因資料，以及分年齡、性別之人口資料，計算高雄市人口各類死因之標準化死亡比，並應用Chiang生命表方法計算高雄市與臺北市人口出生時之平均餘命，以及Tsai et al. (1982)的方法計算重大死因對兩地平均餘命差距之影響。結果：自從1981年以來，高雄市人口幾乎所有死因之死亡率均比臺北市高。2001年，高雄市男、女性人口出生時之平均餘命為73.8年和78.7年，臺北市則為77.6年和82.0年，高雄市人口的平均餘命，無論男女，均與15年前臺北市相似，亦即高雄居民平均餘命較臺北落後了15年，兩地20年來保持著3至4歲之差距。癌症、糖尿病、呼吸系統疾病、消化系統疾病及事故傷害為造成2001年兩地平均餘命差距之主要因素。結論：1981年至2001年間高雄市和臺北市市民平均餘命之差距穩定維持在3至4年，其中62%-65%是由癌症、糖尿病、呼吸系統疾病、消化系統疾病以及事故傷害之死亡率之差別所構成。經由減少機車、吸菸、嚼檳榔、肥胖、增加運動等一級預防工作來降低這些疾病之危險因子，對於縮短兩地平均餘命之差距較會有快速之效應。

　　　　　Objectives: To quantify the effect of major causes of death on the life expectancy gap between Kaohsiung City and Taipei City and provide a research method for the comparison of life expectancy between two populations. Methods: Mortality data from 1981 to 2001 were acquired from the Department of Health. The population census data for the same period were obtained from the Ministry of the Interior. These two data sets were used to calculate the standardized mortality ratios (SMRs) and life expectancy of the residents of Taipei and Kaohsiung. Life expectancy was calculated using Chiang's life table method. The life expectancy gap between Kaohsiung and Taipei was decomposed using a method proposed by Tsai et al.(1982) Results: The mortality rates for virtually all leading causes of death in Kaohsiung were higher than those in Taipei in the past 20 years. In 2001, the life expectancies among males and females in Kaohsiung were 73.8 years and 78.7 years, respectively, which were similar to those in Taipei residents in 1986. The corresponding figures for Taipei residents in 2001 were 77.6 years and 82.0 years, respectively. The gap in life expectancy gaps between the two cities remained at three to four years from the period 1981-2001, of which cancer, diabetes, respiratory system disease, digestive system disease, and injuries accounted for 65% of the gaps for males and 62% for females in 2001. Conclusion: The gap in life expectancy for both males and females between Kaohsiung and Taipei remained relatively stable (3-4 years) from 1981-2001. The differential mortality from the diseases of cancer, diabetes, respiratory system disease, digestive system disease, and fatal injuries accounted for more than 60% of the gaps. Reducing risk factors for these diseases through primary prevention could have long-term effects in closing the life expectancy gaps between the two cities.