Abstract: knowledge service is regarded as the necessary trend in the information transformation and upgrading of library. The library is not only facing continuous improvement and enrichment in the way of knowledge service, but also should focus on the subject of clients in course of service. Client communication action, considered as the subject action during client knowledge exchange and transmission, is important for receiving knowledge service provided by library and extending the service scope for knowledge service. In the course of knowledge service for library, it should pay attentions to the characteristics of client communication action, and its role in transformation of tacit knowledge. Meanwhile, measures should be taken to make obstacles less in the course of client’s knowledge communication actions and promote knowledge communication and co-sharing of cultural situation in library in order that the effectiveness of knowledge service of library and its social value can be both increased.

Key words: communication action