Disclosed is an electroencephalogram signal processing method and device. Acquired electroencephalogram signals are subjected to amplification preprocessing, Kaiser Window processing is performed on digital electroencephalogram signals including alpha wave, beta wave, theta wave and delta wave, and index parameters of the electroencephalogram signals are obtained through amplitude analysis, time domain analysis and frequency domain analysis. The electroencephalogram signal processing device comprises an electrode sensor, a preprocessing device, an analog/digital (A/D) conversion unit, a digital signal processing unit, an output unit, a display control unit and a storage unit. The electroencephalogram signal processing device is combined with a computer software analyzing and processing device, and human-machine operation is utilized to achieve functions of result display, healthcare advice, voice prompt and the like. The electroencephalogram signal processing device is convenient, easy to use, low in cost, maintenance-free and capable of conveniently displaying the current mental state and electroencephalogram in real time for students, white-collar employees and mental workers.