高精度的重复性是保证检测精度的前提，也是精密检测中最重要的指标之一。在Fizeau干涉仪中，干涉腔对环境特别是温度的变化非常敏感，温度的变化和非均匀性是测量的主要误差来源，也是影响测量重复性的主要因素之一。通过研究光在空气中的传播原理，利用Edlen公式建立了Fizeau干涉仪干涉腔的理论模型，并给出了腔长、温度变化大小与干涉仪重复精度的定量关系。理论分析表明，干涉仪重复精度主要跟温度变化大小和干涉仪腔长有关。利用ZYGO公司的干涉仪，通过实验给出了在不同环境中、不同腔长下干涉仪测量重复精度的变化，并与理论计算进行了比较和分析。

High precision repeatability is the precondition of testing accuracy and also one of the most important parameters of high precision testing. In Fizeau interferometer, the interferometer cavity is sensitive to environments, especially to temperature variation. Temperature is also one of the main factors that influence the test repeatability. The interferometer cavity model is established based on Edlen equations according to light transmission theory. The theoretical analysis shows that the repeatability is mainly affected by the cavity length and the temperature variation. The repeatability variation is tested through ZYGO interferometer at different environments and different cavity lengths. The test and computation results are compared and analyzed.