The invention discloses a method for fixing a ZnO nanometer wire in the preparation of a ZnO nanometer wire field effect tube, which comprises the following steps: coating a layer of 9912 photoresist on a field effect tube substrate; after adopting negative photoetching exposure, depositing the ZnO nanometer wire onto the substrate; coating a layer of the 9912 photoresist once more without removing the photoresist and exposing again; evaporating Ti/Au source-drain metal; and fixing the ZnO nanometer wire by utilizing source-drain pad metal so as to fix the ZnO nanometer wire. Due to the adoption of a double-layer photoresist technology, the problem that the nanometer wire falls off the substrate in the process of preparing the ZnO nanometer wire field effect transistor is solved so as to prevent devices from losing effectiveness.