This paper is to examine some issues and policy direction of capital income taxation in Korea. Fundamental tax reform in US was reviewed to get some lessons for reforming the capital income taxation. One of main characteristics in Korea's capital income taxation is different treatment by corporation type, investment goods, and financial structures. Especially, the tax differential for debt and equity financing has been serious, as debt has been deducted as cost. We discuss that tax policy should try to satisfy the efficiency, equity, and simplicity under the structure of income based taxation for the time being. However, the changes of tax policies in advanced economies should be carefully examined, as Korea has the structure of small open economy. The current issue on the abolition of corporation income tax might be premature in logical structure and implementation. The US fundamental tax reform might be useful reference for determining the direction of capital income taxation in Korea, as it gives us some chances to discuss about tax base issue with income and consumption. Consumption based taxation is superior to income based taxation in the perspective of administrative and compliance costs. We should consider these tax costs for reforming capital income tax system in Korea