Photolithography mask and thermal evaporation deposition technology were used to fabricate a thin film devices compatible with electromagnetic shielding infrared window， which could realize the device to possess the efficient anti-reflection of infrared signals in the band of 3~5 μm and shield electromagnetic signals in the frequency band of 12~18 GHz. The cross-sectional symmetric metal grid microstructures which met requirements were prepared on the double-sided polished Si substrate by photolithography mask and vacuum thermal evaporation deposition technology， the highly efficient anti-reflection infrared in the 3~5 μm band was prepared by ion beam assisted electron beam thermal evaporation deposition technology. In order to improve the transmittance of the metal grid further， an infrared anti-reflection film was deposited on the metal grid coating with a cycle g of 550 μm and different line widths. Results show that the peak transmittance of the infrared anti-reflection film at 3~5 μm is 99.8% and the average transmittance is 99.3% through the measurement of vacuum Fourier infrared spectrometer. The electromagnetic shielding effectiveness in the 12~18 GHz frequency band of the metal grid was measured by vector network analyzer， and obtained the overall electromagnetic shielding efficiency of the compatible electromagnetic shielding infrared window thin film device in the 12~18 GHz band is better than 27 dB， the peak transmittance in the 3~5 μm infrared band is 86.3%， and the average transmittance is 86.1%. On the premise of ensuring the electromagnetic shielding efficiency is unchanged（≥27 dB）， the transmittance of the metal grid films has increased by 37.6%（the grid cycle g is 550 μm， line width 2a is 30 μm）. The improvement of shielding efficiency can be achieved either by adjusting the cycle and line width of the grid， or selecting a substrate material with lower resistivity.