Abstract: The bonding surface between the infrared fairing and the fastening ring failed when the pressure resistance test was carried out on the fairing assembly of a certain type of missile. The reasons for the failure of bonding surface were analyzed by means of macroscopic observation, infrared spectrum analysis and energy spectrum analysis. The results show that in the assembly process of the fairing assembly, the excessive amount of grease in the sealing ring caused the bonding surface between the fairing and the fastening ring to be coated with grease, reduced the effective bonding area, greatly reduced the bonding force of the bonding surface, and finally led to the bonding failure of the bonding surface between the fairing and the fastening ring.