Abstract: To calculate the transient infrared radiation released from the terminal-sensitive submuniton,a numerical simulation of the unsteady temperature distribution for the terminal-sensitive submuniton performed by using the software Fluent, which taking into account three factors as follows, aerodynamic heating, irradiative heat transfer and structure heat conduction. Then, the infrared radiation characteristics of both submuniton body and parachute were obtained by calculation at 3-5 m and 8-12 m waveband, the changes of infrared radiation for the whole trajectory were also analyzed. Also, this paper calculated the infrared radiation of atmosphere in the gazing direction, which was compared with the infrared radiation of terminal-sensitive submuniton. The results show that the infrared radiance of parachute is a half of the infrared radiance of submuniton body at least, but the infrared radiation intensity of parachute is 21 times of the infrared radiation intensity of submuniton body at most, and it was preferable to take warning of terminal-sensitive submuniton at LWIR and the deceleration and dispinning stage of the trajectory.