Combined with the optical performance design of infrared detectors, the principle of absorbing and suppressing stray radiation using cold shield blackening layer technology is introduced. Based on the same cold shield structure, three different surface blackening processes are compared, and the physical performance parameters such as the surface absorptivity of the cold shield blackened layer are tested and analyzed. Through the performance test of the infrared detector, the actual influence of different cold shield blackening processes on the performance of the infrared detector is analyzed. The results show that the blackening process of 2# and 3# cold shield can achieve better consistency of surface absorptivity in 2-14 μm band. And in the 8-11 μm band, they have good absorption and suppression of the stray radiation of the infrared detector.