The present infrared imager with unit or line detector cannot obtain wide field with high spatial resolution and high temperature sensitivity at the same time. To solve this problem, a set of wide field thermal infrared imager was developed based on uncooled array infrared detector. The system can realize the 75 ° large field of view, 0.4 mrad spatial resolution and 50 mk (NEΔT) temperature sensitivity. Furthermore, a geometric distortion correction model of array sweeping images was established to solve the low location accuracy and image mosaic crack problems.