An image test system using a CCD and a standard target was established to measure the stabilization accuracy of a gun control system. The principle and structures of the system were introduced. and its key algorithms such as image pretreatment, template matching, the orientation of target cross center and system calibration were investigated. In order to remove the disturbance of the reticle of graduation board on the target cross, the algorithm of the switching median filter was presented. After choosing the grayscale transformation to improve the image contrast, the algorithms for fabricating and matching the template were analyzed and chosen. Then, the orientation algorithms of pixel and subpixel for target cross center were presented. Finally, the angle resolution of the system pixel was confirmed using a calibration method based on active vision. The result indicates that the test accuracy has been better than 0.07 mil, which meets the practical test requirement and implements the stabilization accuracy measurement of modern fire-control systems with stabilized guns in firing ranges.