本文介绍了一种根据激光细丝衍射原理测量直径小于12 μm超细丝直径的方法.本方法通过对细丝衍射的中央明条纹的衍射强度进行最小二乘法拟合，可获得高精度的细丝直径. 本文利用三种不同波长的激光对碳纤维单丝和新疆长绒棉纤维进行实验，利用精度较低的教学光强探测器和智能手机的光传感器收集光强数据，可获得精确的实验结果.

Based on the principle of laser diffraction, a method of measuring the wire diameter which is less than 12μm is introduced. Using the least square method fitting the diffraction intensity of the central bright stripe, the wire diameter can be obtained in high-precision. Carbon fiber and Xinjiang long-staple cotton are used as samples, and three lasers with different wavelength are used to carry out the experiment. It is realized that accurate experimental results can also be obtained by using low precision teaching light intensity detectors and smart phone light sensors.