More and more libraries employ social media to disseminate information in order to broaden the scope of services, to increase user interactions, to bridge the gap with users, and to enable the libraries more visible in the internet age. Although the application of social media software brings many advantages to the library, it also challenges the library. This in turn promotes the move toward adequate planning of social media applications and then to guarantee subsequent practical effects. For the purpose of understanding the application situations, forms and problems of social media software in libraries, this article reviews relevant literatures and analyzes the websites of public libraries in New Zealand. The final goal is to make it a reference for the public libraries in Taiwan.