Aiming at the problems of low production efficiency,poor production consistency and high engineering requirements such as vibration resistance and athermalization in the batch production of off axis three mirror anastigmat system(TMA)in the field of infrared imaging,the traditional manual polishing and other processing techniques are abandoned.In this paper,based on high precision CNC machining technology,the shape and position tolerance,dimension tolerance,surface shape tolerance of elements and other parameters of the machining process are determined.An aluminium based off axis three mirror anastigmat system for mid wave infrared(MWIR)and long wave infrared(LWIR)using an integrated optical mechanical design approach is designed.The system optical parameter are 150mm effective aperture,4× beam expansion ratio,2.8°×2.4° field of view,3.7～4.8μmand 7.7～10.3μmoperating bands.The results of optical design,athermalization design,stress relief design and lightweight design of the system are presented respectively,and the imaging results are tested at room temperature and high and low temperatures.The experiments show that the TMA can meet the imaging requirements of medium and long wavelength infrared systems.