This paper studies the effect of jointly partial elimination of the ten leading causes of death on life expectancy in Taiwan. We find that when all the ten causes of death are simultaneously eliminated, the life expectancy of male and female are incresed by 16.23 years and 13.97 years respectively. At age 0,40 and 65, when the ten causcs are simultaneously eliminated at 10%, 20%, ..., and 100%, the life expectancy increases almost quadratically. At age 0 and 40 the gain in life expectncy of male is greater than that of female, but at age 65 the gain of female is greater than that of male; also at the eliminating rates of 10%, 50% and 100% the gain in life expectancy of male is greater than that of female between age 0 and age 60 while the gain of life expectancy of female might be greater than that of male after age 60. In addition, we investigate the gain of years of working age group. Through adjustments of age and sex, we contruct a regression function of the gain of life expectancy on the percentage of jointly partial elimination of the ten causes. By using the partial regression coefficients (β 's), we can figure out each corresponding percentage of the ten leading causes of death. This can be regarded as the effect of competing risks among the ten leading cuases of death on life expectancy. The higher the corresponding percentage, the more impact. of the cause of death on the life expectancy. By controlling age and sex the order of corresponding percentage of regression coefficients of the ten leading causes of death are Cerebrovascular disease (21.3%), Malignant neoplasm (20.5%), Heart disease (20%), Accident (8.6%), Pneumonia (5.8%), Diabetes (5.8%), Hypertension (5.2%), Bronchitis (5.2%), Nephritis (3.9%) and Chronic Liver Disease (3.6%). This shows the relative effect on life expectancy among the ten leading causes of death at working age group. Based on the cost-benefit standpoint, this result would help allocating the budget for setting an effective preventive programs of the government.