A novel GaAs metal-semiconductor field-effect transistor (MESFET) with Al0.25Ga0.75As/GaAs multiquantum barrier (MQB) buffer layer and narrow band InAs/graded InGaAs capping layer was demonstrated. The MQB buffer layer can improve the sidegating effect and isolation. The capping layer can perform nonalloy ohmic contact with Ti/Pt/Au metals. Furthermore, the Ti/Pt/Au metals directly contact with GaAs active channel layer call work as Schottky barrier. For the fabrication of this novel MESFET, the thermal alloy and alignment processes call be avoided.