The system design is proposed based on 128×128 UFPA(Uncooled Focal Plane Array) of uncooled staring infrared camera. A new kind of TEC's circuit design for IRFPA is emphasized. And the implementation of FPGA for timing sequence of RIOC is also discussed. The method of design is characterized by high integration, high precision, low cost and simple topology. It provides the design idea for the development of the thermal imager system.