Abstract: A periodic structure of bonded GaAs wafers can be used for high power quasi-phase-matched second-harmonic generation of a CO2 laser. The fabrication of the QPM GaAs based on wafer bonding technology and interfacial properties of this crystal were studied. Hydrogen ion beam was used to remove the oxide layer on the GaAs surface to improve its optical properties. Pre-bonding process in the ultra-high vacuum reduced the microspores density of the bonding interface. Heat treatment increased the bonding force. Thus a reliable bond of the two-layer GaAs was realized. The two-layer GaAs combined into a single crystal structure without amorphous layer formed by oxide. By this bonding process a periodic polarization reversed GaAs crystal with large aperture, low loss was obtained, therefore providing a way for realizing high power frequency doubling of CO2 laser using quasi-phase-matching technology.