The present disclosure relates to the field of electronic technology, and provides an EEG processing apparatus and method and a sleep monitoring wearable device, which can reduce complexity of sleep staging. The EEG processing method comprises: obtaining EEG data to be processed (101) analyzing the EEG data to be processed to obtain a predetermined number of segments which do not overlap each other (102) obtaining a maximum value and a minimum value of a peak-to-peak value in each of the segments (103) normalizing a connection line between the maximum value and the minimum value of the peak-to-peak value in at least one of the segments to obtain upper end points and lower end points of the connection line (104) calculating statistic characteristic values of an upper sideband curve formed by the upper end points to obtain a box plot series (105) and obtaining a sleep staging result based on the box plot series (106).