In recent decades, the technological innovation systems (TIS) framework has been applied to the study of technology development and diffusion. While policy is considered a key element of TIS analysis, less attention has been paid to the influence of TIS dynamics on policymaking. To better understand the coevolution between TIS and policies, this paper develop an analytical framework to highlight the coevolution between TIS dynamics and policymaking. The framework underlines not only the influence of policies on TIS functionality, but also that changes in TIS functionality may in turn feed back into policymaking: policymakers may observe changes in TIS functionality and adjust policies to account for this, but changes in TIS functionality may also have implications for the ability of TIS actors to influence policymaking. Empirically, we study the new energy vehicle battery (NEVB) industry in China since the early 2000s. In the case of China's NEVB industry, an increasingly strong and complicated coevolutionary relationship between the focal TIS and relevant policies at different levels of abstraction can be observed. Overall, we argue that more research is needed to better understand the agency side of how TIS development leads to changes in policymaking.