Abstract: Aiming at geosynchronous orbit infrared detection system, the infrared detection performance of the ballistic missile plume is analyzed. The atmospheric transmittance and the background radiance at different heights and different sun zenith angles were computed with the atmospheric radiance model software of PCModWin. According to the obtained results, the performance indexes of infrared system for the plume detection of the ballistic missile, including the effective range, SNR (signal-to-noise ratio) and SCR (signal-to-clutter ratio), were analyzed. The results indicate that SCR performance index can meet the needs of the infrared detection system, but the performance of SNR and the effective range are not satisfactory. The performance of the infrared detection system can be improving the parameters of the sensors and the optical system.