Abstract: The major domestic and international manufacturers of low-light-level image intensifiers predominantly use standard sample comparison methods for detecting fixed pattern noise, relying on predefined reference samples to perform qualitative assessments. However, this method only provides qualitative test conclusions and is not capable of quantitatively detecting fixed pattern noise. To address this problem, this study investigated a method for quantitatively measuring the fixed pattern noise of low-light-level image intensifiers. The method utilizes a high-resolution charge-coupled device (CCD) to capture the output images of the low-light-level image intensifier. Then, grayscale image algorithms are used for analysis and calculation, which realize the quantitative detection of the fixed pattern noise of low-light-level image intensifiers. A test system based on the method developed in this study operated stably. The test results were reliable and could satisfy the requirements of production inspection.