Objective：To evaluate the response control function of patients suffering from obsessive compulsive disorder（OCD）. Meth－ods：Twenty-one OCD patients and 23 healthy controls were enrolled. All patients and healthy controls performed the stop- signal task which provides the indications reflecting the ability of response inhibition：stop signal reaction time（SSRT） and no-signal reaction time（NSRT）. The results of the two groups were ana－lyzed and compared. Results：Both SSRT （376.20±71.92） ms and NSRT （804.33±07.82） ms of OCD group were significantly longer than those of control group （304.13±76.73） ms，（714.98±97.01） ms：t=3.206，P=0.003；t=2.894，P=0.006. After the removal of the influence of NSRT by covariance analysis，the significant difference of SSRT between the two group was still found：F=22.518，P=0.000. The stepwise multiple regression analysis was carried out for SSRT and the other indexes of the task and Y-BOCS score. Con－clusion：The ability of both response inhibition and response executive of OCD patients was significantly decreased.