In deep space exploration, the optical system is susceptible to various factors in space, resulting in instability of the visual axis. In order to improve the imaging quality, high-precision optical axis pointing is required. This paper is designed to feed back the current optical axis pointing in real time during space exploration. Deviation algorithm. We use an improved threshold segmentation algorithm and secondary judgment to improve the accuracy of star point extraction, which can effectively extract star point pixels in real star images. Through the extracted star point pixels, we use a threshold-based gray square weighted centroid calculation method to calculate the centroid of the star point, and use the centroid deviation of the navigation star point to obtain the final optical axis pointing deviation. In addition, we also use the windowing method to speed up the calculation rate after obtaining the navigation star point. Experiments show that the algorithm can feedback the optical axis deviation of the optical system in real time. © 2022 SPIE