A displacement measurement system of spectrum confocal is designed and set up.Gaussian fitting algorithm is used to fit every group of experimental data to obtain corresponding optical wavelength of the peak of spectral response curve.The Levenberg-Marquardt algorithm is used to solve parameter vector of Gaussian function.The system is calibrated by using dual-frequency laser interferometer to find corresponding relationship between optical wavelength and displacements of the reflecting mirror.Precision analysis is carried out on overall system.The experimental results show that Gaussian fitting algorithm is suitable for acting as data processing method of the measurement system

and the calibrating method by dual-frequency laser interferometer can accurately locate position of reflecting mirror.Measurement range of the designed system is 20 mm

measurement precision can reach 10 μm

which can satisfy measurement requirements for certain precision.