By using ZnS/YbF3 five-layer coatings, wide-band infrared antireflective coatings on CaF2 window in the range of 3.4～4.2 μm has been fabricated. The tested spectral results have shown that the average transmittance is above 99%. The wide-band infrared antireflective coatings on CaF2 window can endure the output laser with 200 kW.