Abstract: The low-light-level (LLL) weapon sight measurement under different environment conditions are always interested by military equipment manufacturers. Due to the impact of shock, vibration, shooting, high temperature or low temperature environment as well as other environmental factors, the mechanics, optics and electric performance of the LLL sights will be changed, and the LLL sights can′t function properly. A test and measurement device was designed to test weapon LLL sights operating in different test conditions. The working principle of the detection system established with CCD is given, and the detailed imaging process of the system is analyzed. Based on the calculation of the focal length for the collimator and CCD zoom lens as well as the practical application, the system is deigned with measurment accuracy better than 0.05 mil and the measuring range greater than 40 mil.