A theory framework of motivating R&D professionals’ knowledge sharing intentions based on 2 unit types were built. 339 valid questionnaires were collected and correlation analysis and hierarchical stepwise regression analysis were used for hypotheses testing. A comparative analysis of motivating knowledge sharing intentions in functional and crossfunctional units found that the biggest impact factor of knowledge sharing intentions is ‘enjoyment in helping others’ which belongs to internal incentives, and internal incentives have a significant positive impact on knowledgesharing intentions in terms of functional teams or crossfunctional teams, and team types would moderate the relationship between external incentives and knowledge sharing intentions in such a way that external incentives(organizational rewards) have a significant positive effect in crossfunctional teams, while having a weak negative impact in functional teams.