In recent years, globalization has encountered countercurrents. The “anti-globalization” sentiments such as unilateralism, trade protectionism, and technological decoupling have risen, posing certain risks to the security and stability of China’s industrial and supply chains. This has brought new challenges to the safe development of China’s manufacturing firms. This paper uses data from Chinese industrial firms and China’s customs trade data study the impact of imported intermediate inputs on the output volatility of China’s manufacturing firms. The research finds that there is a critical value for the import intensity by firms. When the import intensity is less than this critical value, compared with non-importing firms, firms importing intermediate inputs have smaller output volatility. When it is greater than this critical value, compared with non-importing firms, firms importing intermediate inputs have larger output volatility. In other words, excessive reliance on foreign intermediate inputs poses risks to the safe development of firms. Therefore, while implementing high-level opening up, the country should also continuously enhance the independent control ability of industrial and supply chains to ensure their security and stability.