A portable and wireless electroencephalography (EEG) device was proposed in this study. The device had following features: (1) the use of dry and flexible electrodes made the device resilient and repetitively used on forehead without conductive gel; (2) the device was small and low power consumption which provided more comfortable wearing. It provided ordinary wireless (Bluetooth) protocol and memory cards to record EEG data. All electronic components were embedded into a portable mechanism conveniently. The device had past Electro Magnetic Compatibility (EMC), Federal Communications Commission (FCC) certifications. (3) EEG data was stored as EDF format compatible with popular EEG analysis tools. This device was good for sleeping study in general. A particular EEG signal Apps could analyze the EEG raw data and provided the sleep quality report in details.