Abstract: R&D internationalization and parent firm innovation performance improvement is an important issue of transnational management. Based on existing researches, this paper reviews various arguments about this issue:the relationship between R&D internationalization and firm innovation performance are positively correlative, negatively correlative, non-linearly correlative (inverted U-shaped relationship, U-shaped relationship, S-shaped relationship) or non-correlative. Based on this, we put forward three sources of different relations between R&D internationalization and innovation performance:first, the definition and measurement of key independent variable (R&D internationalization) and dependent variable (innovation performance) introduced in the main model; second, the sources of differences reflected in the main effect model, including research sample choice and R&D internationalization phases; third, the moderate factors that influence the relationship between R&D internationalization and innovation performance, including parent firms' international expanding experience, complementary capability, technology diversity, organizational slack and political resources; subsidiaries' type and absorptive capacity, characteristics of firms' international R&D network, such as R&D alliance partners type, linkages among alliance partners, R&D network efficiency and the position at the R&D network; and host country factors, such as the technical resources endowment and institutions. Based on the literature review, this paper establishes an eclectic theoretical and empirical research framework including both moderating and mediating mechanism on R&D internationalization and innovation performance. Finally, future directions of research on R&D internationalization and innovation performance are presented, which will provide important basis for subsequent researches.

Key words: R&D internationalization, innovation performance, main effects, moderating effects