In order to slove the Control problem of intake air amount of aviation aircraft engine , design a simple structure, high reliability Mach annunciator. when the Mach of Inlet reaches a set value M, the mach annunciator provides a signal to the engine inlet ramp-conditioning systems. Mach annunciator selection mechanical membrane cartridge as the sensor signal. Through theoretical analysis and calculation to measurement principle of M number, the mach annunciator is designed and manufactured according to the results of analysis，mach annunciator can meet the requirements of the engine inlet automatically adjust.