实验研究了光学系统不同F数下的激光干扰效果。测试了暗背景下、无激光干扰时CCD输出图像的噪声灰度和分布概率。通过比较光学系统不同F数下的激光干扰图像和灰度分布，发现各灰度级的像元数随F数的减小近似线性增加，而并非指数或者对数增加。最后基于夫琅禾费衍射理论，仿真了五边形光阑产生的衍射图样，仿真结果表明在F数较大时，激光干扰图像正是光阑的衍射图样。研究结果可为评估光电成像系统在不同F数下的激光干扰效果提供技术支持和理论参考。

The laser disturbing effect under the different F number of optical system has been investigated in the experiment. We measure the noise grey value and its distribution probability of CCD output image under the dark background and no laser disturbing. According to comparing laser spot image and grey scale distribution under the different F numbers, it is found that the pixel number of different grey scales linearly increase with the gradually decrease of F number, not exponentially or logarithmically. At last, the diffraction pattern of pentagonal stop is effectively simulated based on the theory of Fraunhofer diffraction. The simulated results show that laser spot image is just the diffraction pattern of stop at the large F number. The research results can provide technical support and theoretical reference for evaluating laser disturbing effect of electro-optical imaging system under the different F numbers.