This study used a panel data set, which is including 15 OECD countries that have high income per capita for the time period of 1995-2011. Following causality and autoregressive distributed lag (ARDL), paper yields: 1) respectively the largest and the smallest impacts on health expenditures are caused by public spending and the influences of Age Dependency Ratio Young (ADRY); 2) income and Age Dependency Ratio Old (ADRO) on health expenditures are positive; 3) another striking inference is that while young working population rate is increasing, health expenditure is decreasing.