This present study tested whether job stress mediates the relationship between workload and safety behavior of members in organization. In addition, we hypothesized trust in leader/coworkers functions as moderator between not only the workload-job stress link, but also the job stress-safety behavior link. In order to investigate the hypotheses, 841 employees in various fields of companies were sampled. Using structural equation modeling(SEM), we conducted moderated mediation model analysis which elaborately investigated the significance of our hypotheses. The results indicated that job stress mediated the link between workload and safety behavior of members. In addition, the relationship between workload and job stress was moderated by trust in leader/coworkers. Moreover trust in leader/coworkers moderated the job stress-safety behavior linkage. The implications and limitations of our study and suggestions for future research were discussed.