Abstract: Aiming at the light-spot positioning in the digital simulation image for the target observation and aiming in the target-tracking simulation systems, a method for the light-spot positioning based on monocular vision was proposed. Firstly, the rough positions of the light-spot in the camera image plane were predicted with the Kalman filter method. Then the light-spot image region with the center of the rough positions was obtained. Secondly, the precise positions of the light-spot center in the image were extracted based on the Hessian matrix in the light-spot image region. Finally, according to the positioning model calculation which was established from the point in the camera image plane to the point in the digital simulation image, the positions of the light-spot in the digital simulation image were obtained knowing its precise positions in the camera image plane. Experiment results show that the RMS error for the light-spot positioning is 0.4 pixel, and the time of processing each image is 0.32 ms. The proposed method can locate the light-spot in real time with high dynamic and high precision in the target-tracking simulation systems.