This study utilizes a difference-in-difference (DID) regression model to evaluate the impact of China’s “National Sustainable Development Plan of Resource-Based Cities (2013–2020)” on economic growth in resource-based cities. The analysis is based on the data covering 329 Chinese cities during 2006–2019. Economic growth is measured by the annual growth rate of gross domestic product (GDP). It was found that the policy had a significantly negative impact on economic growth. Further analysis suggests that the policy depressed innovation in resource-based cities, and these cities did not expand their labor and capital inputs. These two phenomena can help explain why the policy’s effect on economic growth was negative, rather than positive. Moreover, our study reports that the effect of the policy was heterogeneous across different cities, depending on their development stages and spatial locations. Overall, our study detects an undesirable effect of the policy. The research findings call for more actions to promote macroeconomic growth during the process of economic transformation in China’s resource-based cities.