Abstract: Star tracker is current widely used optical sensor in spacecraft attitude control system which produces the most accurate measurements. The overall design description, application and qualification results of a novel separated autonomous miniature star tracker were introduced. The novel separated type star tracker successfully operated in-orbit on a large variety of different satellite platforms such as scientific experiment, telecommunication and earth observation. The novel star tracker has applied in-orbit with a total of 21 sets of products up to now. According to the real time telemetry data packages under real in-orbit conditions, the main qualification features are sensitivity 5.7 Mv, update rate 8 Hz, accuracy 2.6, sun exclusion 28, tracking slew rate 1 ()/s. The novel separated type star tracker was the first APS based star tracker ever flown which was adopted in AOCS closed loop control. A full analysis on ground qualification campaign was carried out successfully on the novel star tracker and an in-flight qualification was also achieved, with more than two years information from 20 other star trackers on different satellites. In flight results are in accordance with results obtained from ground night sky tests. The analysis results allow an almost complete validation of star tracker major requirements: accuracy, robustness, availability and reliability.