Using firm-level R&D data with regional international talent data, we find that international talent increases the R&D investment of Chinese manufacturing firms, a result that is further confirmed with patent data and under a number of robustness checks. These findings stem from two mechanisms: international talent boosts human capital accumulation and provides a diversified labor force. Further, the R&D promoting effect is stronger if firms are located in eastern China rather than in other regions, of small and medium-sized rather than large-sized, of domestic ownership rather than foreign ownership. The policy implication is, the introduction of international talent can be a new way to promoting R&D investment, especially for skilled-labor constrained countries. and examine the impact of ITI on firms' R&D investment in China. The results indicate that ITI increases the R&D investment of Chinese manufacturing firms, and the promoting effect is stronger if the firms are located in eastern China. Further, ITI increases the R&D investment of small and medium-sized firms (SMEs) more than large-sized firms, and increases the R&D investment of domestic firms but not foreign firms. In addition, using patent data, we confirm the positive effect of ITI on firm-level innovation. These findings suggest that the introduction of international talent is a new way to promoting firm-level R&D investment, and it is especially important for SMEs and domestic firms which are more resource constrained.In the theoretical literature, several mechanisms, such as a human capital accumulation effect and a labor force diversity effect, have been posited to explain the influence of immigration on innovation. On the one hand, the former effect states that ITI increases the number of research workers and enriches the local knowledge base,