Abstract: A sanitary napkin has a top layer, an absorbent layer and a bottom layer with a sensor layer. The absorbent layer has a hollow portion covered with a silk-made cover layer and has multiple holes defined in the cover layer, wherein some silk cloth filled inside the hollow portion. By having the hollow portion with silk cloth, the menstrual blood is drained quickly and absorbed by the absorbent layer to keep the sanitary napkin dry at the top layer and to avoid toxic vapor. Moreover, the holes on the cover layer provide a ventilating efficiency and the silk is cool to be contact so that muggy feeling is efficiently reduced. The sensor at the bottom layer conveniently indicates the changing occasion to the user.