For high performance air craft engine disks, high-performance Ni-based wrought superalloys (e.g. U720Li™, AD730™) with over 40vol% of the γ' phase at 600-700 °C have been developed. Applying them to gas turbines is expected to improve the efficiency. However, due to their low workability, it is difficult to make large size components. We have developed a new innovadve process (the MH process) to improve the workability of high-performance Ni-based wrought superalloys. The strengthening mechanism of these γ' precipitation-typed superalloys is widely known to be enhanced by the coherent interface between the y phase and γ' phase. We focused on the incoherent γʹ phase that precipitated on the y phase grain boundary during forging and it was found that the incoherent boundary shows no strengthening effect. Formation of y/incoherent y' two-phase microstructure would dramatically improve their workability. Cold working was achieved by applying the MH process to the U720-type alloy AD730. The MH process made it possible to fabricate cold rolled sheets, cold drawn wires and the forged turbine blades. It also exhibited excellent ductility at high temperature; we obtained 99% reduction of area at over 920 °C and 500% elongation at 950 °C by applying the MH process. It was demonstrated that U720Li can be processed by die forging at low temperature and high strain rate without using superplastic forming. In this study, we investigated how the heat treatment condition affects the formation of unique microstructures with good hot and cold workability.