Inclusion Criteria:  Outpatients or inpatients who met the diagnostic criteria of DSM-5 or ICD-10 for depressive episode of bipolar disorder. Willing to participate in clinical research and sign informed consent 12 ≤ age ≤ 18 HAMD-17 score ≥ 17; HAMD-17 item 1 (depression) ≥ 2, and YMRS ≤ 12 Physical examination, laboratory examination, vital signs and 12 lead ECG showed that the physical condition was stable. If any test results are beyond the normal range, they can be included only if they are judged to be abnormal or deviated from the normal values but have no clinical significance or belong to reasonable conditions in the study population. Such decisions must be recorded in the subject's original file and signed by the researcher  Exclusion Criteria:  Besides bipolar disorder, the diagnosis includes schizophrenia, schizophrenic affective disorder, schizoid disorder, depression, dissociation disorder, borderline personality disorder, material dependence, autism, organic mental disease, etc Other conditions except bipolar disorder were diagnosed, such as schizophrenia, schizophrenic affective disorder, schizophrenia like disorder, depression, dissociation disorder, borderline personality disorder, material dependence, autism, organic mental disease, etc. according to the judgment of the researcher, the patient is at risk of suicide or injury to others, or HAMD-17 item 3 Score ≥ 3, or attempted suicide in the past six months Patients with rapid circulation type; Those who had suffered from serious heart, liver, brain, lung, kidney and other serious diseases in the past or at present, and the researchers considered that they were not suitable for the study; The results of Biochemistry, hematology, electrocardiogram or urine test were not within the normal value range of the laboratory at the time of screening, and had clinical significance according to the judgment of the researchers (except for the abnormal indexes of reasonable condition in the research population, such as abnormal blood glucose and blood lipid indexes); The subjects received electroconvulsive therapy (ECT) within 6 months before enrollment; There was a history of malignant tumor or complications; Known allergy history or complications to test drug or ingredient (with previous history of allergic reaction caused by drug, rash, urticaria, etc.); Pregnant and lactating women and patients unable to take appropriate contraceptive measures during the trial period; Patients with previous suicidal behavior or existing strong suicidal tendency and patients with serious excited and aggressive behavior.