Abstract: To reach the requirement of optical elements in the aerospace infrared remote sensor being highly transmissive and thermally diffusive, this paper proposed a reticular microstructure with the wavelength selection characteristic. The characteristic parameters of the reticular microstructure were designed based on the equivalent medium theory and mathematical modeling theory, and Matlab was used to simulate the spectral radiant characteristics on the reticular microstructure surface. The microstructure was fabricated by plasma etching, and its surface topography was analyzed by scanning electron microscope (SEM). The results reveal that the reactive gas flow rate, RF power and the chamber pressure are critical for the morphology of the microstructure and the steepness of sidewall. By optimizing and analyzing the parameters, the experimental results illustrate that the transmission diffraction efficiency of the microstructure achieved over 91.5% at an operating wavelength of 10.6 m under optimized conditions. This can basically fulfill the requirement of reticular microstructure for aerospace infrared remote sensor utilization.