Objective · To compare the therapeutic effect, cost, cost-effectiveness and utility between internet-based cognitive behavioral therapy (ICBT) and cognitive behavioral group therapy (CBGT) in the patients with obsessive-compulsive disorder (OCD). Methods · Twenty-eight patients who met the OCD diagnostic criteria of Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) were assigned to ICBT group (n16) and CBGT group (n12) according to the patients willingness. Both groups were treated for 6 weeks. The study compared differences in the severity of OCD and symptoms of anxiety and depressive at baseline, during treatment and after treatment, as well as differences in cost, cost-effectiveness and utility between two groups. Results · There was no significant difference in the scores of Yale-Brown Obsessive Compulsive Scale (YBOCS), Self-rating Depression Scale (SDS), Self-rating Anxiety Scale (SAS), and Visual Analog Scale (VAS) [a component of EuroQol Five Dimensions Questionnaire, (EQ-5D)]between the two groups at baseline (P0.291, P0.114, P0.478, P0.799). After treatment, the YBOCS scores decreased compared to pre-treatment in two groups. There was no statistical difference in subtraction rate of YBOCS between the two groups (P0.291). The SDS scores of ICBT group also decreased after treatment compared to pre-treatment (P0.003). The average cost per patient in ICBT group was 2 710.50 yuan less than that in CBGT group. When one YBOCS score per patient reduced, ICBT group spent 281.33 yuan less than CBGT group. The VAS scores were significantly improved after 6-week treatment and ICBT group has a more significant improvement. Conclusion · ICBT and CBGT have comparable and significant efficacy. And ICBT is a lower cost and more cost-effectiveness and utility treatment than CBGT.