The Efficacy And Safety Of Mitizodone Phosphate Tablets In The Treatment of Patient With Major Depressive Disorder

Inclusion Criteria: * 1.a Man or a woman with major depressive disorder(MDD) as the primary diagnosis according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria (classification code 296.22、296.23、296.32、296.33) * 2.Has a Montgomery Åsberg Depression Rating Scale (MADRS) total score of 26 or greater at Screening and Baseline Visits. * 3.Has a Clinical Global Impression - Severity of Illness (CGI-S) score of 4 or greater at Screening and Baseline Visits. Exclusion Criteria: * 1.has major depressive disorder with psychotic features according to the DSM-5. * 2.Current or history of: bipolar disorder、schizophrenia、anixety disorder、insomnia、any substance abuse or dependence and other psychiatry disorder as defined in the DSM-5. * 3.Current or history of a clinically significant neurological disorder (including epilepsy、Alzheimer disease, Parkinson disease, multiple sclerosis, Huntington disease). * 4\. has Serious body disease such as neurological disorders、cardiacvascular disorders、hepatic disorders、 renal disorders, blood system disorders and endocrine disorders. * 5\. Current or history of cancer( except basal cell of the skin and preinvasive carcinoma of cervix uteri). * 6\. Current or history of angle-closure glaucoma. * 7\. has made a suicide behavior in the previous 1 year ，or has a score greater than or equal to 4 on item 10 (suicidal thoughts) of MADRS . * 8.has taken fluoxetine within 4 weeks prior to initial dosing. * 9\. has taken other antidepressive medications or antipsychotic medications within 2 weeks prior to initial dosing. * 10.has psychotherap at Screening and/or Baseline Visits. * 11.has had physiotherapy within 3 months prior to initial dosing. * 12.Has an alanine aminotransferase, aspartate aminotransferase or total bilirubin level greater than 1.5 times the upper limits of normal. * 13.Has an alanine aminotransferase, aspartate aminotransferase level greater than 2 times the upper limits of normal；or total bilirubin， direct bilirubin，creatinine level greater than 1.5 times the upper limits of normal；or a thyroid stimulating hormone value outside the normal range. * 14.Has an abnormal electrocardiogram confirmed as clinically significant by the investigator. * 15.Has a history of severe allergies.