Japan's economy is declining since the impact of the economic ¡§foam¡¨ in the 1990s. Besides, under the double blow of Asian financial storm many enterprises go bankrupt, reforming happens frequently day by day within the territory of Japan. Japanese steel industry does not make an exception. In order to increase the occupation rate of market in the industry or for the goal of long-lasting operation, the actions of merger and alliance among the steel factories are prevailing. According to the positive attitude of the steel blast furnace factories to deal with this sitution they established their own trading department one after another. Make the demands of trading, information and finance services provided by the trading companies who live by the steel blast furnance factories go down, it force the companies to adopt the action of cooperation or merger to prevent disappearing in the industry. This study utilizes the case study approach to deduce the management model of the merged enterprises and induce with the phenomenon. According to the secondary and case interview materials collected to proceed an exploratory qualitative research. Case study aims the new established company composed of the isolated steel departments of Itochu and Marubeni with equal stakes. Probes into its tactics goal, merger motive, merger process related to the operation performance and try to establish a management model of merger. This study found that the direction and method of decision while carrying out merger originally, and the unique national and corporate culture in this case improve to reach the anticipated synergy achievement on the initial stage of merger. And provide suggestions and references to companies which intend to merge with similar culture and background.