Integer coefficients filters,based on MATLAB,are designed to extract the 40Hz EEG.Since the collected EEG may be mixed with Eletromyographical interference that comes from the scalp,eye movement and so on ,the EEG in the frequecy of 40 Hz is completely covered,therefore,EMG interference should be considered when extracting 40 Hz EEG.So in this paper,the 80Hz composition beyond a certain threshold is regarded as the existence of EMG interference.By the method of consistency detection between the two channels of 80Hz and 40 Hz,the part of 40 where their coincidence rate reaches a certain extent will be rejected,leaving the true paroxysmal 40Hz EEG,so that 40Hz EEG auto-detection is achieved.