Abstract: In order to enhance the transmittance of infrared windows and domes,a dual-waveband antireflection coating on ZnS substrate is developed.The design involves a multi-layer structure of ZnS and YF3 as high and low refractive index coating materials.The experimental results show that the antireflection coatings have high transmission in the spectrum of medium-wave infrared and long-wave infrared.This structure shows an average transmission of greater than 92% in 3.0~5.0 μm range and 90% in 7.0~10.0 μm range.The coatings have endured for the environmental test.