This is a randomized, double-blind multi centric clinic study. Both of therapist and patient are blind. There are 180 patients from 3 hospitals included, who meet DSM-IV criteria for major depressive disorder, the score of HAMD-item＞20，＜35；and meet the criteria for TCM syndrome of "Liver Qi stagnation and Transformation of Stagnant Qi into Fire". Patients are randomized to JWXY and sertraline treatment groups, receiving oral sertraline (start with 50 mg/day for one week then continue with 50 mg/day) plus placebo of JWXYJN; or oral JWXYJN plus placebo of sertraline daily for 2 months. The symptoms of depression and anxiety are measured with HAMD and HAMA tests at baseline and at 2，4，8 weeks; and LFT, BUN, Cr are assessed at baseline and end of program. Then data will be analyzed with SPSS software to determine the efficacy and safety of JWXYJN comparing to sertraline in the treatment of mild to moderate major depressive disorder.