In order to meet wide-field,high image quality and easy portability of infrared detection equipments,a large field transmissive infrared collimator system with working band of 8~14 μm,full field ≥24 °,aperture of 130mm was designed.A simple three-type telephoto lens structure and a non-spherical were used to solve the problem that how to balance the three transmission systems aberration.According to the theory of optical design optimization of multi-level system design,eventually a infrared transmissive collimator system was obtained, the MTF at 20 lp/mm was not less than 20%,distortion resolution rate infinity was less than 1% in the whole field of view and the position of each focal length corresponding to different wavelengths.The advantages are wide field of view,high resolution,good image quality and simple structure,which can provide high image quality,high-resolution infrared target source at infinity for a variety of infrared imaging,military infrared detection system performance parameters sights.A prototype application was developed and applied to verify alignment test.The results show that the prototype can get clear and accurate images to meet testing requirements.