Hardware communication circuits based on field-programmable gate array (FPGA) module on im. age processing boards of infrared thermal imaging systems are designed and implemented. Serial communication and first-in-first-out (FIFO) reading and writing modes are used in the circuits. On one hand, control data from PC are received and replied in real time by communication circuits. On the other hand, control information interchange is performed through FIFO and data signal processor (DSP) module on image processing boards to form bidirection. al communication links among modules. Special serial communication chips such as TL16CP754 used on tradition. al image processing boards are not adopted in the design. Functions of the chips are realized by FPGA, so the de. sign area and cost are saved. Integration and stability of the system is improved. It is easy to be a miniature and low cost system. Simulation and experiment results show that the design is correct and the system works stably.