The micropyramid structures was integrated into the silicon nitride thin film. The refraction, diffraction and interference of the thin film optical microstructures which contains interface were comprehensively utilized to realize the regulation of transmission and reflection.The preparation of micro-pyramid array in SiNx film by single-point diamond turning technology combined with nano-imprint and inductively coupled plasma etching was presented. The large-area, high-efficiency, low-cost microstructure preparation method was applied to generate thin film optical microstructures. The thin film optical micropyramid structures with different sizes were fabricated. The structural unit size could be adjusted between 1.5 μm and 10 μm. Spectral characteristics test results proved the ultra-wide band anti-reflection of the SiNx thin film optical micropyramid array during near-infrared to long wave infrared region. In the near-infrared band of 0.8~2.5 μm, the reflectivity is less than 1.0%. In the mid-infrared band of 3~5 μm, the reflectivity is less than 2.5%. In the long-wavelength infrared band of 10~12 μm, the average reflectance is less than 5%. Compared to antireflection film,the anti-reflective effect of SiNx thin film micro-pyramid structure array can be achieved without the refractive index matching in the design of the films, which simplifies the structure of the films. It is also found that the SiNx thin film micro-pyramid structure array has induced transmission enhancement characteristics at near-infrared. The SiNx thin film micro-pyramid array with a height of 2 μm to 4 μm have obvious transmission-induced enhancement effects at the wavelength of 2.1μm, and the micro-pyramid structure array with a height of 4 μm and a bottom width of 8 μm has the most obvious transmission enhancement effect, and the transmittance reaches 96% at least. The position and intensity of transmission enhancement are determined by the morphology, size and structure proportion of the micro-structure based on experimental test and simulation analysis.