设计了一台双光路自相关的透反射率测量系统，实验测试了3种不同形态激光作光源时，系统的单点透反射率重复性精度，验证了光源的功率和偏振稳定性对此系统的影响较小。在验证性分析的基础上完善了系统的稳定性，并对系统精度进行校准。实验结果显示，在置信度为95%时，系统的重复不确定性能稳定在0.04%左右，满足大口径低透射率、低反射率光学元件均匀性测量的精度要求，为此类仪器设计提供了参数选择依据。

A two path and self-correlation system is designed to measure reflectance and transmittance. In order to verify and modify the stability of this system, repeatability of reflectance and transmittance for single-point is tested and analyzed by using of three different laser sources, and it concludes that the power and polarization stability of the system does little reaction with system repeatability. Stability is enhanced based on experimental analysis, what’s more, system accuracy is calibrated. The result turns out that the uncertainty is stabilized at 0.04%, which fits well with the accuracy requirement of uniformity measurement on large-aperture optics with low transmittance or reflectance, and concrete parameter selections are provided to the instrument design of this kind.