Zinc selenide (ZnSe) is widely used for infrared (IR) optical systems because of its wideband transmission region. However as a substrate,it is very difficult to deposit ultrabroad band multilayer antireflection (MLAR) coatings in IR region,especially for the durability. 2-16 μm ultrabroad band MLAR coatings on ZnSe are designed and produced many times by ion beam assisted electron-beam deposition. The absorption rate of YF3 at 3400 and 1640 cm-1 is found by deposition single ZnSe and YF3 films on Ge substrate. Finally,2-16 μm ultrabroad band MLAR coatings are deposited by using BaF2 and YF3 as the low-index materials. DLC films are deposited on external MLAR coatings by pulsed vacuum arc ion deposition.The measured results show that the average transmittance is greater than 93%,the peak transmittance is higher than 97% and the durability,stability are both advanced.