针对提高反射相位延迟测量速度和精度的应用需求，研发了一种以起偏器-棱镜-检偏器(PPA)为光路结构的测量系统，基于最小二乘法，给出了无需知道初始检偏角可对所采集的光强分布点进行二元线性拟合的方法，进而提出了对不同起偏角情况下所采集的两组光强分布点进行多次拟合、逼近求交得到反射相位延迟量的方法。该方法在反射相位延迟的测量过程中，无需精确设置光学元件的方位角，可利用软件系统完成光强分布点的采集及其计算机数值计算处理，所有的测量操作可控制在15 s 内完成，实验结果表明：反射相位延迟测量结果的误差为0.005 rad，重复性为0.0016 rad。

In order to satisfy the demand of the measurement for reflection phase retardation with high precision in a short time, a measuring system based on the typical optical structure which is composed of polarizer, prism and analyzer (PPA) is presented. By means of least-squares method, a binary linear analysis is employed to fit the intensity distribution points which are captured without knowing the initial analyzer angle. Then, two sets of intensity distribution points captured under the different conditions of polarizing angle are processed with the methods of repeated fitting and approximation to obtain an intersection, which is just the measured value of reflection phase retardation. In this approach, data collection of the intensity distribution as well as the associated numerical calculation can be performed via software system without setting optical elements′ azimuth accurately. Moreover, all of the measuring operations can be completed in 15 s. The experimental results show the error of the measured result of reflection phase retardation is 0.005 rad and the repeatability of which is 0.0016 rad as well.