This study explores the link between workload and work performance among junior high school teachers under China's "Double Reduction" policy. The study employed a quantitative approach, surveying 1,135 junior high school teachers from various regions in China. Utilizing the NASA Task Load Index (NASA-TLX) to measure workload and a binary structure model to assess performance. Post-implementation of the policy, teachers reported a significant increase in workload across all dimensions (mental, physical, temporal demands, effort, and frustration). This increase was negatively correlated with both task and contextual performance. However, while most dimensions of workload negatively impacted contextual performance, mental demand had a positive influence. The findings suggest that despite the policy's aim to alleviate burdens, it has inadvertently increased workload and impacted teachers' performance, with the exception of a positive effect on certain performance aspects. The study contributes to the understanding of the complex dynamics between teacher workload and performance, offering insights for educational policymakers and administrators.