Photonic crystals (PC) with low emissivity have high reflectance, and they will become bright targets under strong radiation from high temperature environment. Further researches on PC characteristics are made in order to let PC have adaptive capacity to environment and fuse with background well within a pretty broad luminance range. Six PCs, with emissivity of 0.116、0.212、0.307、0.519、0.606 and 0.718, are designed and made by the method of changing PC period. PCs are jointed into four PC pattern paintings (PCpp), and they are covered on the surface of simulation target. The target and background are observed by the 8～14 μm thermal imager, and their mean radiant temperatures of each time point are recorded. Euclidean distance between target and background and camouflage efficiency of the target under this background are calculated by radiant temperature. Compared with the results, it is found that camouflage efficiency is 76.92%, when the temperatures of PCpp with emissivity of 0.212、0.307 and 0.606 are in the range of 292～302 K, the Euclidean distance between the mean temperature of PCpp and the temperature of the grass background is 12.55 K, and the limit temperature difference ΔT0 is 4 K, which can make the target and the background fuse well.