One of the distinguishing features of Web 2.0 is the overlapping role of the Internet users and information providers which is broken the traditional thought of ”authority” or ”mono-information resources”, and shifts the main power, the Blog is the typical result of a Web 2.0 age. During this time, downloading and reading are not the only required function, whereas uploading and sharing are the factual reasons for Internet users' participation. Taking with Web 2.0 and Blog spirit, this article interprets the probability of using Blog as a marketing tool as well as the new problems confronting public libraries, and then there are several suggestions of using Blog for reference.