Tacit knowledge sharing (TKS) is important to improve the teaching skill and researching knowledge of university teachers. In this paper, the tacit knowledge sharing of university teachers is catalogued as four modes from perspectives of the psychological risk and psychological value which are measured by two grades--high and low. The four modes are named "Peer-review", "Learning Community", "Thumb-a-lift" and "Academic Conference", which are characterized by different values and risks. Some suggestions are proposed to promote the tacit knowledge sharing of university teachers.