Abstract: In order to obtain the distribution of delay amplitude of the elastic modulator across the entire aperture, the theoretical and simulation analysis of its delay distribution law was conducted, and on this basis, an experimental measurement system was built for verification experiments. The measurement system generated modulation signals through an optical path with polarization devices, and then used a digital phase-locked device to accurately match the received signal with the local reference signal in terms of frequency and phase, thereby achieving signal demodulation. Finally, the demodulated signal was transmitted to the upper computer to calculate the relevant phase delay parameters. Simultaneously, a precise two-dimensional displacement platform was used to achieve full aperture movement of the elastic optical modulator, thereby enabling measurement of all positions. At the end of the experiment, the upper computer saved the phase delay parameters at each coordinate and imported the data into the drawing software to achieve intuitive visualization of the phase delay amount, and the simulation software was used for theoretical simulation comparison. According to the comparison between experimental results and theoretical values, the relative error of the measurement was 0.13%, and the two-dimensional distribution of the delay of the elastic light modulator across the entire optical aperture was obtained, which was consistent with theory and simulation. A precise calibration method for the entire aperture of the elastic light modulator was presented, which provided references for large aperture, high-precision polarization modulation, and detection.