Parole rejection/approval of inmates is subject to the decision-making of the parole board members of each prison. Previous studies have found that many factors influence the decision of the parole board. This study introduces Decision Making Trial and Evaluation Laboratory (DEMATEL), which is commonly used in commercial and industrial fields, to further explore the subjective factors parole board members consider in parole decisions. This study surveyed 20 parole board members in Taiwan and the results show that the major factors affecting the decision-making of parole boards include crime characteristics and offender recidivism risk, with crime characteristics being the most important factor.