The author constructs a model tO test the effects of knowledge traits and mechanism to knowledge transfer within transnational corporations（TNCs）, in which the ‘tacit’, ‘simple-embedded’, ‘network-embedded’ and ‘transfer mechanism’ are supposed to influence knowledge transfer, and ‘transfer mechanism’ can be a mediator between knowledge traits and success knowledge transfer. After empirical testing, the direct effect of ‘tacit’, ‘simple-embedded’, ‘elementary mechanism’ and the mediator effect of ‘secondary mechanism’ are proved in the process of knowledge transfer within TNCs