Against the backdrop of restructuring global value chains and the complex, volatile economic and trade relations between China and the United States, U.S. demand for Chinese intermediate goods exhibits high uncertainty, profoundly affecting the operational security of Chinese enterprises. Using multi-regional input-output tables from 2012-2024 and data on Chinese A-share listed companies, this study measures the uncertainty of U.S. demand for Chinese intermediate goods and empirically examines its impact on corporate operational risk in China. The findings reveal that uncertainty in U.S. demand for Chinese intermediate goods significantly increases the operational risk of Chinese enterprises. This effect operates through three channels: reducing asset turnover, tightening trade credit, and raising administrative expense ratios. A higher proportion of overseas income amplifies the impact, whereas cash holdings serve as an effective buffer. The adverse effects are more pronounced among non-state-owned enterprises, firms in western China, and those with higher dependency on supply to the U.S. market. Accordingly, it is recommended to establish a cross-departmental industrial chain risk monitoring and early-warning system, formulate more targeted and differentiated policies, and encourage enterprises to strengthen resilience building and construct multi-dimensional risk defenses.