In order to measure aero-engine parts’clearance precisely

an application research on capacitance method clearance measurement is carried out

and it mainly designs a capacitance method clearance measurement application system based on the programmable capacitance-digital converter AD7746.Driven cable is used to avoid parasitic capacitance’s influence on measuring results and enhance its anti-jamming ability

wide measurement range and high precision can be achieved by configuring compensation registers of AD7746.This system is tested many times on the own-designed experiment platform

which shows that expected targets are achieved with nice linearity

good repeatability and high precision.Finally a scheme of engine’s tip clearance measurement by capacitance method is given.