This study addresses on interactions of economy and environment in a dynamic computable general equilibrium (CGE) with a focus on greenhouse gas (GHG) mitigation strategy in Korea. Whether Korea has to reduce the greenhouse gas or not, it has large influence on Korean economy, such as changes in GDP and welfare. The GDP decreases by 0.113~0.132%, and the marginal abatement costs are 110~123 $US per metric ton of CO2 for Korea. In the case of reduction of Greenhouse gas in Korea, the output in fossil fuel and energy intensive sectors are decreased sharply. Therefore, we should be exempted or delayed from the international reduction programme of greenhouse gas abatement targets within the limits of the possible.