In order to ensure the high-precision pointing of bracket for star sensor after installation, a technical method for quantitative grind of bracket for star sensor was proposed. Firstly, we established the star sensor bracket’s coordinate system by constructing the virtual horizontal axis, then obtained the angle relationship between any two coordinate axes by the theodolite interactive measurement and sequential solving strategy. According to the results, we got the posture transformation matrix between star sensor bracket’s actual coordinate system and the space camera’s coordinate system. By the technical requirements of the star sensor bracket’s installing, we acquired the posture transformation matrix between the ideal star sensor bracket’s coordinate system and the space camera’s coordinate system. Then, we obtained the posture transformation matrix from the actual coordinate system to the ideal coordinate system by bridge of the camera coordinate system. According to this result, the corrective value of bracket for star sensor was accurately solved. The experimental research shows that this method can improve the star sensor bracket’s pointing accuracy from the initial 760″ to less than 10″ after two rounds of iteration, which proves effectiveness of the method. At the same time, directivity calibration and correction of bracket for star sensor can also guide the precise assembly and adjustment of other two components with spatial free angle relationship.