For the CCD serial star images, if there is a high bright star in the field of view, the CCD readout circuit voltage can be over high and the same line or column gray value of the CCD image is on the high side, a light line traveling across the star centre is formed in the image. As the bright line exhibits great similarity to the motion of space targets, and disturbs greatly target detection and identification performance, it must be eliminated. Based on the analysis of the star-sky image, an automatic detection algorithm of bright line in star-sky images is put forward. With the isotropy property of star imaging and auto-registration character of Fourier transform, the algorithm can automatically detect and eliminate the bright line both in space domain and frequency domain. Experiments of 3 groups of star-sky images (60 frames per group) show that the algorithm can automatically detect bright line with high accuracy.