This paper identifies the causal effect of U.S. multinationals' technology shocks on their subsidiaries' and nearby domestic firms' productivity in China. By combining firm-level data from both the U.S. and China, I match U.S. multinationals with their manufacturing subsidiaries in China and measure the multinationals' technology shocks to the local firms in China based on the multinationals' patenting activities in the U.S. To address potential endogeneity concerns, I introduce an instrumental variable strategy based on U.S. state-level R&D tax credit policies.