iResearch reveals that the scope of global B2B e-commerce will be reaching 26 trillion dollars, with the rising of the Internet and e-commerce has changed the rules of the international trade development, business must be changed with the external environment, and the ability of growth and decline of their own conditions, continued to adjust its international marketing mode in order to ensure long-term profitability and growth of enterprises. This study is focusing on the case study of the way to do net marketing of small and medium trading business, incorporated with electronic commerce (EC) and search engine marketing (SEM), to develop a set of trade developing model of the net marketing. In the future, small and medium trading business is dedicated in net marketing services, not only B2B electronic commerce can be used as reference as one of the options, but also through B2C electronic commerce to enhance the ability to develop overseas market. In addition, search engine marketing (SEM) is a good tool to promote the corporate website as well. The using of Pay-Per-click (PPC) could be advertising to attract the attention of local market. Search engine optimization (SEO) is meaning to adjust the HTML structure and content of corporate website to be raised the ranking in the search engine, and reduce the cost of international marketing.