Knowledge has become one of the most important strategic resources to build the sustainable competitive edge for many firms. Knowledge sharing and knowledge transfer are the necessities of R&D collaboration, moreover, they will affect the cooperative performance. Unfortunately, knowledge is not able to be transferred and absorbed completely due to some factors, thereby knowledge damage is produced and leads to difficult transferring even failure. At first, this paper defines knowledge damage. Then the factors, which lead the formation of knowledge damage, are analyzed. Based on these, some measures to reduce knowledge damage are provided. We expect the means will promote the knowledge being transferred successfully.