An infrared small target detection system is designed,using C6416 DSP as core processor,and FPGA as coprocessor.Main algorithms is realized on two parallel C6416,and image preprocessing on FPGA.Local threshold binarizing method based on two-sliding-window is adopted,and image preprocessing technology is used to improve segmentation effect.Jamming target is removed using frame coherence of the moving target.Experimentation has shown that,the system has good target detection effect and real-time performance.