The invention relates to the technical field of a system for treating depression based on 3D printing ear molds. The system comprises a nervus auricularis vagi stimulation system, a mobile equipment module, a hospital PC terminal, a maintenance terminal and a cloud server, wherein the nervus auricularis vagi stimulation system comprises a pulse detecting module, a bluetooth module, a state displaymodule, a power supply module, a DC-DC adjustable voltage-increasing voltage-stabilizing module, a first voltage increasing module, a second voltage increasing module, a third voltage increasing module and a data processing module; and the stimulus frequency is 15-30Hz, the output current is 1-10mA ( 250 omega load impedance), the output power is 0.1-0.3VA ( 250 omega load impedance ), the pulsewidth is 0.2ms +/- 30%, and the treatment course is timed to 20-40min. According to the system for treating depression, provided by the invention, stimulus parameters are set, so that data in brain waves and the depression can be well combined for analysis, and the effect of stimulation for treatment is exerted.