Provided is a double-faced metal bonding method of a terahertz quantum cascade laser device. The method comprises a crystal-orientation aligning process for an epitaxial wafer and a high-doped substrate wafer, a low-temperature metal bonding process and a semi-insulating substrate corrosion process and the like. Finally, an epitaxial structure layer growing on a semi-insulating substrate wafer issuccessfully transferred to the other high-doped substrate wafer. The method can guarantee crystal orientation consistence between two bonded wafers and prevent the laser device from being mechanically damaged due to crystalline anisotropy in the cleavage process; the problems of non-uniform corrosion and over-corrosion caused by insufficient selectivity of corrosive fluid can be prevented, and corrosion uniformity and completeness are guaranteed. The method accords with the standard semiconductor technological process, operation is simple, convenient and efficient, and the method is suitablefor industrial mass production.