The reason that a firm have to run its business in diversify ways, is to extend contents that it produced, enhance its business values and gain more benefits. Diversification has two kinds of business models, which is vertical and horizontal diversification. As for a steel company, vertical diversify is use its main business as the core, then extend to other new territories of steel business. A firm, which uses internationalization strategy, has several internal and external factors. The internal factors, which are like domestic market is to small, rise to the labor costs, values of people change, traditional industries move abroad, and lack of lobar power. For external factors is free market economy, change of the business environments. To lower the cost, company has to integrate domestic and abroad advantageous resources. The firm has to advancing its own competitiveness by internationalization. Corporation merge is for the purpose of expanding the organization scale and operation abilities, and to pursue growth of external businesses. By buying target company¡¦s properties, to reach the goal of corporation merges. With the transnational merge can also achieve the internationalization strategy. The integration and re-engineering of working process, is the key task after to take over the management of the merged company. To co-operate with company strategy, review the resources needed during the integration. To plan and design the method of improves working process. And to start the implementation. To review the achievements of the integration and improvement of the working process. Can be judged by key events, which defined by different main manufacturing and managing issues. And with review in each phase, the effective of improvement could be ensured. For every company, every important decision made. Will lurking with several uncontrollable factors. To face with the risks, which are coming from any miss-judgment or fails decisions during the merging process that could ruin the whole merging process. In conclusion and suggestion section, we will discuss more about the best processing model of merging task.