Bonding　of　GaAs/GaN　was　successfully　achieved　at　600°C　in　N2　atmosphere　for　1h,　with　two　different　chemical　pretreatments　of　hydrophilic　and　hydrophobic　processes.　Both　methods　can　achieve　high　bonding　strength　and　large　bonding　area.　Based　on　the　mechanics　of　the　two　different　pretreatments,　the　transmittance　of　the　bonding　interface　with　different　pretreatments　was　studied.　Results　of　the　transmission　spectrum　indicate　that　the　hydrophobic　process　can　yield　a　higher　transmittance　of　94.7%　at　630　nm.　Devices　were　fabricated　to　execute　the　EL　spectrum　measurement,　the　results　of　which　are　consistent　with　the　transmission　spectrum.