With the rapid development of Internet, E-mail virus-marketing has been studied theoretically by experts all over the world. This essay introduces the E-mail virus-marketing’ definitions, characteristics and significance, and analyzes the E-mail virus-marketing strategy for small and medium enterprises’ network marketing to provide effective reference. E-mail virus-marketing is not spreading by HIV virus, but based on 'mailing list' of the Internet to provide customers with free products and services in internet, and achieving the purpose of promotion. Customers are willing to spread information of company, the speed of spreading like a virus. E-mail virus-marketing has been taken by large enterprises. Based on these strategies, we may see the E-mail virus-marketing strategy has its own characteristics. So it is necessary to grasp the characteristics to circumvent its shortcomings and elements of the Network E-mail virus-marketing for small and medium enterprises who will implement the E-mail virus-marketing. According to their own business, small and medium enterprises should apply the E-mail virus-marketing Strategy reasonably in order to promote the image of enterprises and products.