CCD采集TwymanGreen干涉图时常出现异常干涉条纹，阻碍观察者对真实条纹的判断与精确测量。针对此种现象，基于莫尔条纹的形成机理和CCD的空间结构，从理论上分析此非正常条纹为等厚干涉条纹与CCD空间结构形成的莫尔条纹。通过对光场分布的计算和Matlab数值模拟，调整各参数，重现此种条纹，进一步验证了理论解释的正确性。莫尔条纹对精细干涉条纹的观察有妨碍作用，实验中应当避免使用分辨率相当的CCD进行采集，或可通过改变CCD探测器的采样算法，使莫尔条纹效应减弱甚至消失。

Twyman-Green interference plays an important role in high-precision optical measurement. Anomalous interference pattern often appears in TwymanGreen Interferometer when CCD is used as an image sensor, which prevents scientific researchers from recording and testing real pattern accurately. Therefore, the principle of optical Moir and the spacing structure of CCD are used to analyze the anomalous interference pattern, which is proven to be Moir pattern theore tically. Based on the optical field distribution calculation, numerical simulation is used to recover the anomalous pattern to further verify the theory. Moir fringe hinders the observation of interference fringes and should be decreased or even eliminated by using a proper CCD or changing the CCD detector sampling algorithm.