Plant is production unit which consists of hardware for manufacturing like machinery, equipments and software for its installation like design, construction, supervision, engineering, know-how and trial operation. In the view of this, plant industry can be defined as an aggregation of manufacturers and sellers of plant. In this study, I would like to present the direction of cooperation for mutual benefit of Korea-Japan by understanding international competitive power of both countries' plant industry, which is not only growing as a national strategic industry, but also occupying the most important part in international economic cooperation.