Abstract: To calibrate the phase characteristic of a Liquid Crystal Variable Retarder(LCVR) attached with a compensator. For LCVR, under 25℃, 405 nm wavelength, the total of 141 experimental samples were obtained by the built setup based on Stokes parameters, in which 71 samples(calibration set) were used for model calibration, and 70 samples(prediction set) were used to validate the calibrated model independently. Least Squares Support Vector Machine(LSSVM) and Support Vector Machines(SVM) was used to calibrate model. Test results show, for prediction model based on GASVR, PSOSVR, LSSVM, the maximum wavelength deviation are respectively 0.013 6、0.013 7 and 0.004 5, the mean square error is increased by 2 times, and the phase retardation of all the wavelengths and all the voltage values of LCVR in the effective working range could be rapidly and accurately obtained by the LSSVM model, thies the prediction model based on LSSVM was an effective mean for LCVR phase calibration.