In order to accord with the two principles of generalizeness and uniqueness, the paper has analyzed the effectives of international R&D on host countries’ R&D productivity and mechanism with the path converged design based on OECD, EU15 and other 8 countries during 2000-2012. The paper has discovered that crowding-out effect of international R&D on host countries domestic R&D investment is the leading cause, otherwise the factor productivity effect based on comparing the empirical result between high income countries and the low income countries. Crowding-out effect comes from the inhibiting effect on entrepreneurial spirit of host countries of international R&D and then through the crowding –out effect the international R&D could decrease the factor productivity for R&D.