Epidemic prevention policies during COVID-19 are considered effective ways to protect lives, but the dramatically changing work and lifestyle under those policies significantly impact occupational stress. Based on the panel data of job stress checks from 2018 to 2021, this study explores the time and individual heterogeneity in the impacts of the pandemic on occupational stress. Following the job demand-resource theory, we further identified the most affected group of employees, given their workplace factors. Our findings show that, on average, occupational stress was alleviated initially in 2020 but deteriorated again in 2021. By examining the heterogeneity effects, we found that less motivated employees are more likely to experience a significant fluctuation in high-stress risk due to the pandemic. Providing adequate workplace support is expected to mitigate the high-stress risk, especially interpersonal relationships, support from managers, job meaning, job control, and work-life balance. Motivated employees experienced higher occupational stress in the early phase of the pandemic, while less motivated employees tended to have higher occupational stress in the following years of the pandemic. The most effective workplace factors to mitigate the negative pandemic impacts on occupational stress vary across the years, requiring continuing studies to understand and provide person-centered coping solutions.