Objective To investigate the clinical efficacy of low-frequency repetitive transcranial magnetic stimulation （rTMS） combined with fluvoxamine in the treatment of children and adolescents with firstepisode obsessive-compulsive disorder （OCD）. Methods A total of 58 children with first-episode OCD who met the diagnostic criteria of the American Diagnostic Statistical Manual of Mental Disorders Fifth Edition （DSM-5） from June 2021 to March 2022 in outpatient and inpatient department of Qingdao Mental Health Center were selected. All children were randomly and double-blindly divided into experimental group and control group， with 29 cases in each group. The experimental group was treated with low-frequency rTMS combined with fluvoxamine， and the control group was treated with pseudo-stimulation combined with fluvoxamine. Both groups were observed and treated for 8 weeks. The Yale-Brown Obsessive-Compulsive Disorder Scale （Y-BOCS）， Hamilton Anxiety Scale （HAMA）， and Treatment Emergent Symptoms Scale （TESS） were used to evaluate he efficacy. The severity of OCD and anxiety of the two groups were analyzed and compared by repeated measures analysis of variance （ANOVA） before treatment， and at the end of 2nd， 4th， 6th and 8th week of the treatment. The total effective rate and the incidence of adverse reactions between the two groups were compared. Results The differences in scores of Y-BOCS and HAMA before treatment between the two groups were not statistically significant （P ＞ 0.05）. The differences in the score of Y-BOCS between the experiment group and the control group at the end of 2nd， 4th， 6th and 8th week ［（26.10±5.11） vs （30.24±3.79）， （22.48±5.09） vs （25.76±4.60）， （17.34±5.15） vs （20.31±5.65）， （12.59±5.82） vs （16.31±6.71）］ were statistically significant （P＜0.05）. The differences in the score of HAMA between the experiment group and the control group at the end of 2nd， 4th， 6th and 8th week ［（19.41±4.02） vs （22.55±3.88）， （15.62±4.53） vs （18.90±3.39）， （11.66±3.11） vs （15.62±3.23）， （8.31±2.19） vs （12.55±2.68）］ were statistically significant （P＜ 0.01）. The results of repeated measurement ANOVA showed that the Y-BOCS and HAMA scores of the two groups had inter group， time and interaction effects， and the differences were statistically significant （P＜ 0.05）. Further analysis found that the experimental group had an effect at the 2nd week of treatment （P＜ 0.001）， while the control group had an effect at the 4th week of treatment. The total effective rate ［93.11%（27/29）］ of the experimental group was higher than that of the control group ［72.41%（21/29）］， and the difference was statistically significant （Z=1.980， P＜ 0.05）. There was no significant difference in the incidence of adverse reactions between the two groups ［37.93% （11/29） vs 27.59% （8/29）］ （χ2 =0.704，P ＞ 0.05）. Conclusions Low-frequency rTMS combined with fluvoxamine in the treatment of children and adolescents with first-episode OCD can significantly improve the obsessivecompulsive symptoms and anxiety symptoms of children， with a high treatment efficiency， and obvious curative effects can be achieved within 2 weeks.