The exterior elements of the linear array satellite will change over time, resulting in significant degradation of the geometric positioning accuracy of the image. It is necessary to conduct geometric calibration of the camera in a quick and timely manner. Therefore, this study proposes a geometric calibration method through a star observation which satellite could be implemented at any position in orbit. The linear array camera point to the deep space and aim at the star for shooting. The star coordinate extracted from the image was regarded as the control point to calibrate the exterior elements of the camera. Then the geometric positioning accuracy of the image is improved. In this study, several Jilin-1 linear array satellites have been verified. The satellites with different launch times were used for star observation, and the geometric positioning accuracy was better than 50 m after the calibration by star observation method.