Repetitive transcranial magnetic stimulation (rTMS), like electroconvulsive therapy, has become a new treatment tool for psychiatric disorders as a non-pharmacological treatment, especially its effectiveness in treating depression has been widely recognized. 2008, repetitive transcranial magnetic stimulation was officially approved by FDA as a treatment for depression in adults. 1. Basic principle and parameters of repetitive transcranial magnetic stimulation Basic principle of transcranial magnetic stimulation: Usually an “8” shaped insulated coil is applied and connected to a capacitor, which is placed on a specific part of the scalp, when the current from the capacitor is instantaneously discharged through the coil, a pulsed magnetic field of certain intensity is generated around the coil. This local pulsed magnetic field will pass through the scalp and skull in a direction perpendicular to the coil and enter a certain depth of the cortex. The rapid alternation of the current intensity will create a pulsed magnetic field, which in turn will generate an induced current in the neural tissue of the cortical surface. Different psychiatric disorders and clinical symptoms and individual differences require different treatment parameters to achieve good therapeutic results, i.e., an individualized treatment plan. The parameters set include stimulation site, stimulation intensity, stimulation frequency, number of pulses attended per day, duration of treatment per day, number of treatments per week and number of treatments in a course of treatment. The dorsolateral prefrontal cortex (DLPFC) is the most commonly used site. The left primary auditory cortical area is chosen for the treatment of tinnitus. The intensity of stimulation is generally based on the ipsilateral Motor Threshold (MT), which is generally 80% to 110%, and the higher the intensity, the stronger the penetration. The treatment frequency can range from 0.3 Hz to 20 Hz, generally not more than 30 Hz, the most commonly used 10 Hz, the stimulation frequency can be divided into high frequency and low frequency. Low-frequency stimulation is generally ≤1 HZ, which can inhibit ipsilateral local neuronal activity by preferentially activating γ-aminobutyric acidergic neurons in the cortex, reducing the excitability of the cerebral cortex, and also having an inhibitory effect on the contralateral side. High-frequency stimulation, generally ≥3-5 HZ, can increase cortical excitability by activating glutamatergic neurons to ease local neuronal activity. The number of daily stimulation pulses, duration of treatment per day, number of treatments per week, and number of sessions per week vary widely in the literature. the parameters recommended by the FDA for the treatment of depression are 10 HZ stimulation frequency, 120% MT stimulation intensity, 3,000 pulses per day, and more than 37.5 min per treatment. This is usually done daily, 5 times a week, with the number of treatments varying from 20 to 30. 2, depression Whether high-frequency dorsolateral prefrontal stimulation on the left or low-frequency dorsolateral prefrontal stimulation on the right, patients in the treatment group can be shown to be more effective than the placebo control group. Earlier studies had small sample sizes, short sessions of repetitive stimulation, relatively low stimulation intensity, and insignificant effects. After several years of exploration, current repetitive transcranial magnetic stimulation can be extended to at least 4 weeks or more (20 sessions), with stimulation intensities varying from 10% to 120% MT and up to 3,000 pulses per session. rTMS for depression is one of the most studied in psychiatric disorders, with approximately 30+ publications to date taking a completely randomized controlled approach. Several meta-analyses have been performed on these studies, and most of them have shown a greater superiority of the experimental group over the control and sham rTMS stimulation groups. Two recent meta-analyses also showed the same results. Therefore, it is certain that rTMS is effective in the treatment of depression and also shows some effects in some refractory depressions. rTMS is mostly accepted for the acute treatment of depressive episodes, and it has been reported that patients without drug resistance, without anxiety and with more severe depression may have better results in the acute treatment. 3. Adverse effects and risks The most serious adverse event associated with the use of rTMS is the induction of unexpected convulsions. The incidence of seizures induced by rTMS is only 1 in 1000 in the current study, which is less than the incidence of seizures with bupropion, tricyclic antidepressants and antipsychotics. The incidence of transient headache after treatment is about one tenth, but the duration is short, the degree is mild, and no special treatment is generally needed. For bipolar disorder, there are reports of occasional induced mania. After stimulation with different frequencies and intensities in healthy volunteers, it was found that there were no significant effects on cognitive function, language fluency and EEG, and no interictal seizures were seen. Some scholars have reported that rTMS can induce interictal seizures in both normal and interictal patients, but the stimulation frequency is mostly between 10 and 25 Hz and the stimulation intensity is above the threshold intensity. Therefore, the adverse effects of rTMS are much less than those of drugs and ECT. In conclusion, TMS is safe, easy to tolerate, and suitable for outpatients and inpatients. Currently, high frequency stimulation of the left DLPFC or low frequency stimulation of the right DLPFC is recognized as a treatment for depression in adults. It is believed that more studies will be conducted in the future to explore the efficacy of rTMS in the treatment of psychiatric disorders, making it a powerful tool for the treatment of psychiatric disorders.