Knowledge communication methods are various during the knowledge conversion processes, they can be described by four features: expressive form, intermediary form, real-time/non-real-time,one-way/interactive. The knowledge social network can be found by formal knowledge transfer organization or informal knowledge transfer relationship. Social networks also provide the motivations for learning. We give a real case of knowledge transfer in the education and career of a student and analyze the functioning mechanism of social network in the knowledge transfer process