The accurate calibration of the phase-delay voltage curve is the key to achieving high precision polarization measurements using a nematic Liquid Crystal Phase Variable Retarder (LCVR). An accurate and efficient automatic measurement system was established to improve the accuracy of the liquid crystal retarder delay measurement. Firstly, a new measurement method was proposed, which combined the light intensity method, the Soleil compensator method, and the equal deviation measurement technology, to solve the problem of low measurement accuracy or the low efficiency of the existing methods. A measurement system was developed to overcome these challenges, and automated measurement of the system was realized by Labview technology, which further shortened the system measurement time. Finally, the experimental errors, repeatability, and the working efficiency of the system were verified experimentally. The experimental results show that the system delay measurement error is less than 0.0575%λ, the repeat accuracy is less than 0.0197%λ, and 100 delayed sampling points can be automatically measured in 30 minutes. The system is suitable for the accurate calibration of the phase delay-voltage curve of a liquid crystal variable retarder in the visible range.