The invention an FSK-SSVEP demodulation system and demodulation algorithm, belonging to the field of brain-computer interface. The system consists of three modules: an SSVEP stimulation generator, anEEG signal acquisition device and a signal processing. After receiving the start signal, the subjects gaze at a specific stimulus; the EEG signal is collected and the command signal is obtained through a demodulation algorithm, and the subjects are prompted to stop gazing at the visual stimulator, thus stopping the data acquisition. The EEG signal acquisition device is used for collecting the SSVEP EEG signal generated by the subject through the fixation stimulation device, and the collected EEG signal is wirelessly transmitted to the software signal processing platform of the intelligent terminal. After receiving the EEG signal, the software processing platform performs preprocessing on the stored signal, and FSK-SSVEP signal demodulation and command recognition, and finally analyzes theeffective components of EEG signals and judges the commands that the subjects are watching.