By using the methods of literature research and network investigation, this paper analyzes the successful cases of social media marketing in foreign libraries in recent years, sums up its marketing characteristics, and puts forward the enlightenment to the social media marketing of Chinese libraries from the two aspects of marketing plan and marketing strategy, that is, to determine the marketing objectives, design the marketing contents, select the promotion tools, participate in user interaction and follow-up feedback evaluation are the core steps of the marketing plan. By finding the right marketing entry point, integrating social resources, expanding the scope of marketing, mobilizing the whole library to participate in and rely on new technologies to carry out precision marketing, the effectiveness of library social media marketing can be improved.