Obsessive compulsive disorder (OCD) is a kind of mental disorder which is characterized by intrusive thoughts and ritual behaviors. In recent years the failure of inhibition has been widely used as the reason of obsession and compulsion. As a result, the question of whether the failure of inhibition exists on OCD patients preoccupied researchers’ attention. Unfortunately, during the past two decades, although there were plenty of research findings in this field, there were still many limitations, the first of which was the long-standing contradictory conclusions about the existence of inhibition difficult on OCDs due to all the different tasks applicable to the study of inhibition. Moreover, the cognitive neuropsychological mechanisms of inhibition haven’t been extensively studied. Based on the problems mentioned above, we explored the existence of the failure of inhibition by means of experiment and the co-occurrence of inhibition difficult on GADs was studied simultaneously. In particular, whether it has the effect of inhibiting or promoting effect in obsessive compulsive disorder is a need to solve the problems in the current research. Therefore, the international relatively new inhibition and promotion mode will be adopted to explore the inhibitory and promote effect of patients with obsessive-compulsive disorder and whether they have a common influence on patients with obsessive-compulsive disorder in this study. The study used behavioral experiment to explore this issue. 75 subjects were selected to attend the experiment, including 25 patients with obsessive-compulsive disorder, 25 patients with anxiety disorder and 25 healthy subjects. The measurement tools included DSM-IV-TR, Yale-Brown Obsessive-Compulsive Scale, Beck Anxiety Inventory and Wechsler Adult Intelligence Scale. Chinese Affective Picture System designed by Bai, Ma, Huang and Luo(2005) was chosen as experiment materials. The whole experiment was performed on a PC machine. Experimental design was single factor experiment. Among them, the independent variable is the group (the patients with obsessive-compulsive disorder, anxiety disorder and normal control group), and the average response time of the test is the dependent variable of the test. In particular, the average reaction time of the subjects was mainly included in the promotion and inhibition of the task of the time point 1 and the time point of the time point of the 2 images to stimulate the reaction time. The main results were as follows: (1) There were two potential mechanisms that might led to the failure of inhibition on OCDs named facilitation and inhibition. By means of a task that could separate the two effects, we found that the failure of inhibition was the main mechanism which led to OCD. Compared with inhibition, the effect of facilitation was negligible. (2) Inhibition of the difficulty is a unique mechanism for patients with obsessive compulsive disorder, rather than the "shared substance" in patients with anxiety disorder "