Objective To investigate the clinical effects of dynamic psychotherapy combined with fluvoxamine in the treatment of obsessive-compulsive disorder（ OCD） and the influence on the psychological defense mechanism. Methods A total of 80 OCD patients who were treated in Mental Health Center of Xi'an City from January 2012 to December 2016 were selected and randomly divided into two groups according to the order of adnission with 40 cases in each. The control group was given fluorosamine therapy， while the observation group were treated with dynamic psychotherapy combined with fluorosamine therapy. The clinical effects of the two groups were determined by Yale-Brown Obsessive Compulsive Scale（ Y-BOCS） and Hamilton Anxiety Scale（ HAMA） before and at 1st， 4th， 8th week after treatment. The Defense Style Questionnaire（ DSQ） was recorded before and after treatment in two groups. Results The scores of Y-BOCS and HAMA at the 4th and 8th week after treatment decreased in both group， and the scores of the observation group were obviously lower than those of the control group， with statistical significance（ P＜ 0.05）. After 8 weeks of treatment， the total effective rate of the observation group（ 72.5%） was higher than that of the control group（ 52.5%）， and the difference was statistically significant（ χ2=4.501， P=0.034）. After 8 weeks of treatment， the mature defense mechanism increased and the immature defense mechanism decreased in both groups， and the observation group was superior to the control group， the difference was statistically significant（ P ＜ 0.05）. Conclusions The clinical effects of dynamic psychotherapy combined with fluvoxamine in treatment of obsessive-compulsive disorder was obviously better than the single use of fluvoxamine， which could significantly improve patients' psychological defense mechanism.