This study is focused on the industrial symbiosis based on industrial ecosystem theory. At first, the concept of industrial ecosystem was introduced. Industrial symbiosis is a good tool in order to make a harmony between industry and natural ecosystem. The good example of industrial symbiosis is the case of Kalundborg in Denmark, where 11 networks are working in four enterprises and one community nearby. It was proved that savings of natural resources and economic benefit are achieved by use of industrial symbiosis. Moreover, the control of pollutant emission was also done by use of advanced technology and investments. Based on this case, It was shown that industrial symbiosis through eco-industrial complex in Korea was confronted with many difficulties. First of all, loose emmision criteria, recycling system on wastes, and the absence of will for industrial symbiosis should be solved in Korea.