Objective: To provide objective basis for diagnosis of depression by Supper EEG Technology (S-Et) and determination of neurotransmitters, such as 5-HT, acetylcholine, dopamine, norepinephrine. Method: 244 of depression patients and 71 normal controls were involved in the study. TCM syndrome differentiation, S-ET and neurotransmitters determination were applied to the cases. Result: The comparison showed that depression patients and normal controls had significant differences in 5-HT, ACH, DA NE and EXC(p<0.01, with lowered levels in the patients). There were also marked differences in S-ET between TCM syndromes and normal controls (p<0.05). Conclusion: The brain function of depression demonstrated by S-ET is different from the normal persons. The mechanism of depression is not a simple elevation or decrease in all the neurotransmitters.