This paper is concerned with the assessment of major regional development strategies such as the three Coastal area development strategies (East Coast Development, South Coast Development, and West Coast Development) and the Seoul- Pusan development corridor strategy in terms of efficiency and equity. Multiregional Computable General Equilibrium for Korea is developed to capture the economic impact of regional investment expenditures, estimating the time-series influences of regional development alternatives on economic growth, inflation, welfare, income distribution, and interregional economic inequality for ten periods. In a sense that the main point of concern in the national development planning of Korea is with the question of improvement of national competitiveness with more equitable interregional income distribution, it is necessary to promote the West Coast region rather than the Seoul-Pusan development corridor. The West Coast regional development can lead to substantial gain in GDP and reduction in regional income disparity. In a multinational economic perspective, this regional development is expected to contribute to the economic cooperation of Northeast Asia and to enhancing the joint comparative advantages between China and Korea. However, it might worsen the income inequality in the long run.