Infrared scene projector is essential and standard equipment for training and testing IR threat detection systems including missile warning systems and hostile fire indicators.DMD as one of the scene generator used in IRSP has performed several attractive features including high spatial resolution,high framerates,no dead pixel and excellent uniformity.In this paper we proposed a new structure of DMD based IRSP.We use a field lens and a mirror as separator to achieve a wide field-of-view optical system design.Since the field lens is a part of the illumination path as well as projection path,it brings several challenges to the optical system design.In this approach we detailed analyze the design method and perform test equipment and facilities we developed.