Taking meteorologic observation as the application target, the optical system design of thermal infrared camera based on microbolometer detector array was presented. The optical system has a focal length of 60 mm, spectrum band is 8?14 μm, field angle is 7
. The infrared objective lens was designed based on complicated Cooke configuration. Analysis shows that the lens imaging performances approach diffraction limitation. Objective was also designed with athermalization. The results show that in the temperature from －20℃ to 60℃ the lenses have a favorable performance with imaging spot diagram which is approximately equal to Airy disk diameter.