With increasing demand for the high Mach number aircraft, it is necessary to extend the operation range of the impulse wind tunnel to the middle and low Mach numbers, especially with the wide Mach number range operation capability. The Ludwieg tube, due to the advantages of low cost, convenient adjustment of parameters and high quality of flow field, has been developed and applied in the sub/transonic/supersonic and hypersonic field. The development status of wide Mach number range impulse wind tunnels are analyzed, and the key technologies of Ludwieg tube tunnel which need to be solved when applied in wide Mach number range are summarized, including the wide Mach number nozzle design technique, the external tube heating technique and the high temperature and pressure isolation technique.