Background:The underlying mechanisms of the relationship between stressful life events and obesity among Chinese workers are unclear.Objective:This study aimed to understand the processes and mechanisms involved in stressful life events, unhealthy eating behavior, and obesity among Chinese workers.Methods:From January 2018 to December 2019, a total of 15,921 government employees were included at baseline and they were followed-up until May 2021. Stressful life events were assessed using the Life Events Scale, and unhealthy eating behavior was assessed using four items. BMI was calculated as weight (kg) divided by height (m2) using physically measured data.Results:Overeating at each mealtime (OR = 2.21, 95%CI: 1.78–2.71) at baseline led to reports of higher risk of obesity at follow up. Eating before going to bed at night sometimes (OR = 1.51, 95%CI: 1.31–1.73) or often (OR = 3.04, 95%CI: 2.28–4.05) at baseline led to reports of higher risk of obesity at follow-up. Eating out sometimes (OR = 1.74, 95%CI: 1.47–2.07) or often (OR = 1.59, 95%CI: 1.07–2.36) at baseline led to reports of higher risk of obesity at follow-up. Stressful life events were not directly associated with obesity, but unhealthy eating behaviors, including overeating at each mealtime (β = 0.010, 95%CI: 0.007–0.014; β = 0.002, 95%CI: 0.001–0.004, respectively) and irregular meal timing (β = −0.011, 95%CI: −0.015–−0.008; β = −0.004, 95%CI: −0.006–−0.001, respectively), significantly mediated the associations between stressful life events at baseline and obesity at both baseline and follow-up.Conclusions:Unhealthy eating behaviors mediated the relationship between stressful life events and obesity. Interventions should be provided to workers who have experienced stressful life events and unhealthy eating behaviors.