Obsessive-compulsive disorder (OCD) is a chronic, disabling, mental disorder, which has been linked to significant abnormalities in certain brain areas, including the orbital frontal cortex and the anterior cingulate cortex. Neuroimaging studies have also shown that brain areas related to the decision-making function include the orbital frontal cortex and the dorsal prefrontal lobes. Furthermore, the association between OCD and decisionmaking function has been consistently demonstrated from a neurobiological perspective. Clinically, impaired decision-making ability is commonly observed in OCD patients, and there is a correlation between OCD and abnormal decision function. Decision-making tasks are typically divided into two types, decision-making under risk and decision-making under ambiguity, with the former commonly evaluated using the Iowa Gambling Task (IGT) and the latter using the Game of Dice Task (GDT). In this article the neural mechanism and evaluation methods of decision making in OCD were reviewed.