With the completion of the deployment of the fifth geostationary satellite in May 2021, all satellites of the entire space-based infrared system are nearly depolyed, and the system's ability to monitor the ground is greatly improved. Based on a large number of relevant literature and public reports, a comprehensive performance analysis of the scanning cameras of all 9 orbiting satellites of the space-based infrared system is carried out. First of all, according to the detector system of the scanning camera and flight-trace characteristics, this paper analyzes its scanning imaging system and calculates estimated values of such key parameters as optical system parameters, detector parameters, ground resolution and sensitivity of all 9 orbiting satellites' scanning cameras. Secondly, to comprehensively analysis and research on the flight characteristics of space-based infrared system satellites in large elliptical orbits and their ground surveillance missions, this paper proves that the optimal in-orbit operation mode is pairwise synchronization, and the difference between the two satellites in a single orbit is 1/4 period. A comprehensive analysis of the flight characteristics and ground monitoring missions of the space-based infrared system geostationary satellites shows that at least two satellites are in good ground observation positions in the mid-latitudes of the northeastern hemisphere. Finally, according to the radiation characteristics of the ballistic missile plume and the detection parameters of the space-based infrared system scanning cameras, the minimum observation height of the missile plume by all orbiting satellites is calculated and analyzed. The results show that the 40°N latitude area in the Eastern Hemisphere can be monitored by more than 4 satellites at the same time, and some satellite-borne cameras have the ability to detect the ignition timing of ballistic missiles.