COVID-19 has gained intense attention globally. However, little is known about the COVID-19-ralated mental health status among workers. The cross-sectional online survey with 123,768 workers was conducted from February 2, 2020 to February 7, 2020 on a mega-size labor-intensive factory in Shenzhen, China. Oral consent was obtained prior to the questionnaire survey. The information collected in the survey included demographic characteristics, psychological symptoms, COVID-19-related information, and demands for psychological education and interventions. Symptoms of anxiety and depression were measured by the Zung's Self-Rating Anxiety Scale and Self-Rating Depression Scale. Logistic regression models were performed to determine the association between related factors and mental health status. The prevalence of anxiety and depression symptoms was 3.4% and 22.8%, respectively. The dominant epidemic-related factors were having confirmed cases in the community (odds ratio [OR], 2.75, 95% CI, 2.37-3.19) and having confirmed friends (OR, 2.44; 95% CI, 1.69-3.52) for the increased risk of anxiety and depression symptoms, respectively. Nevertheless, major traditional risk factors such as general or poor health status and always drinking alcohol were still the dominant factors associated with the increased risk of anxiety and depression symptoms. Overall, 67.3% and 26.8% workers reported desire for psychological education and interventions, respectively. All assessments were self-reported, resulting in a risk of method bias. Our findings show a relatively low prevalence of anxiety symptoms, a relatively high prevalence of depression symptoms, and urgent demand for psychological education and interventions among workers during the COVID-19 outbreak. Copyright © 2020. Published by Elsevier B.V.