Aiming at the defects of traditional detection methods in detecting and tracking micro-satellite that if the detection threshold is set too high,the target may be lost,while if it is set too low,a large number of false alarms will arise,this paper proposes a Track-Before-Detect(TBD) algorithm for micro-satellite by applying the basic concept of TBD to specific scenes.The observation model of infrared sensor is established,the TBD algorithm is deduced,and the specific implementation steps of particle filter are designed.Finally,simulation experiments are carried out to verify the effectiveness of the model and algorithm.