Human factors engineering process is applied in design phase from planning to commission and operation. Twelve elements of human factors engineering need to be linked closely between each information necessary for each element implementation. When a design information is changed, each element needs to be reevaluated in the design process. A design support system for the human factors engineering process, developed and utilized internally by Mitsubishi heavy industries, LTD, is introduced in this paper. This system integrates each information concerning human factors, archives and allows practitioners to manage human factors information in design process execution. This system also allows practitioners to identify what human factors activities need to be reevaluated when design or condition changes are occurred during plant life cycle.