The star sensor, due to the advantages of high pointing accuracy and no attitude accumulation error, has thus increasingly become first choice for various spacecraft attitude sensors. This paper studies the usage system-level strategy of the star sensor after the appearance of early fault symptoms during satellite’s on-orbit operation. A system usage strategy is proposed, which is, the star sensor is powered on only when performing the payload mission with control precision requirements. In the case of no control precision requirements, the gyro integral attitude determination method is mainly used, and at the same time, the star sensor is powered on regularly for attitude correction. Detailed mathematical simulations and on-orbit validations have been carried out for various strategy situations. The on-orbit operation results show that this strategy effectively reduces the power-on time of the star sensor, and at the same time the attitude control indexes can be met, thus the purpose of prolonging the service life of star sensor can be achieved and the ability of autonomous management of satellites in orbit has been enhanced.