It is important for defending near space weapons and detecting near space targets to study the infrared radiation characteristics of near space hypersonic missiles. By studying the near space hypersonic missile X-51A′s flight test,the infrared radiation characteristics of hypersonic missiles are analyzed,and its infrared radiation model is established. The missile skin,engine and tail flame are reguarded as the primary infrared radiation sources of hypersonic missile. Taking X-51A test vehicle as a reference,the infrared radiation strength of near space hypersonic missiles is calculated at different directions in 3~5 μm and 8~14 μm waveband,and the calculation results are discussed.