There are three main findings in the paper.(1) On the basis of the theories from the related disciplines and the research results in the topic, three levels are clarified for conducting a study concerning transnational corporations (TNCs) and regional development, impacts of TNCs on the host region, relationships between TNCs and all participants in the host area, and main factors determining the bargaining power of the two sides.(2) Three interaction systems, namely production chains, organizational structure, and the hierarchy of relations of ownership and possession, plus a regional system are used as background for theoretical analysis.Therefore, it is suggested that the power relations between transnational and the host regions be more comprehensively judged by positing them in the systems.(3) Regional impacts of TNCs on the host regions are characterised as extensiveness, gradation, regionalization, multi-sides, differentiation, and timeliness.The relationships between TNCs and the host regions are complementary, compertitive and evolutionary.The main factors determining the relationships are social political background,structures of TNCs and the host economies, and power positions of the two sides.