Objective:To investigate the prevalence of pre-diabetes mellitus (PDM) and the impact of occupation-related factors on PDM, among workers from a steel company in Tangshan city, Hebei province.Methods:Clustering sampling method was used to select a steel company and to carry out occupational health-related physical checkup programs for eligible workers who had working in this company for longer than one year. The study began in February and ended up in June, 2017. Workers who were with FPG level as ≤6.9 mmol/L, and free from diabetes, were selected as the subjects for this study. Questionnaires were used and physical examinations and FPG testing conducted.Results:The total number of subjects in this study was 4 173, of which 2 648 appeared as pre-diabetic, with the prevalence rate as 63.4 %. Increase of the PDM prevalence was in parallel with the length of service, among the workers. The risk for the pre-diabetes in those who worked more than 8 hours per day was 1.696 times higher than those who worked less than or equal to 8 h/d (95 %CI:1.517-1.937). Compared with those workers without exposures to heat, noise or carbon monoxides, the proportion of pre-diabetes appeared higher in workers exposed to heat, noise or CO with OR=1.782 (95 %CI: 1.205-2.636), 1.815 (95 %CI: 1.209-2.794) and 1.653 (95 %CI: 1.158-2.361), respectively. Risks for those who were exposed to heat or noise were higher than those who were free from exposure to any occupational hazards ( OR=2.098, 95 %CI: 1.296-3.397). Prevalence rates of pre-diabetes in those who were exposed to heat, noise or CO, were higher than that those who were not. Conclusion:Working hours and exposures to heat, noise or CO appeared as influential factors on PDM.