Abstract: Tacit knowledge is becoming a key point to achieve success for knowledge organization. Cognition and sharing of tacit knowledge are also the focal points of knowledge management in organization. The paper makes literature review of tacit knowledge cognition from definition, characteristic and classification of tacit knowledge, and points out that cognition of tacit knowledge needs further research from above three aspects and also needs further research based on individual and cognitive psychology. At the same time, the paper makes literature review of tacit knowledge sharing from ways, factors and management actions, and points out that the tacit knowledge sharing needs further research from motivation of sharing, quantitative research of sharing efficiency and process of sharing