In the context of the harsh measurement conditions of aeroengines, this thesis analyzes the advantage of microwave sensors for the blade tip clearance measurement, and the basic structure of the blade tip clearance measurement system based on microwave is described followed by its principle of the measurement. Finally, the effectiveness of the system is proved on the dynamic experimental system, and the main influence causes are analyzed in detail. It can help the practicality application on the aeroengine test.