In order to gain the performance index and special requirement for the information fusion device of millimeter-wave/infra-red (MMW/IR) dual-mode composite seeker, the optimal software and hardware design plan of the information fusion system was designed and the testing and evaluating rule was formulated for information fusion system. Finally, the hardware of information fusion system was tested through the testing software for the testing system, and the results for this system proved the correctness and reliability for the hardware system, and the validity of data validating arithmetic was also validated effectively, and the practicality of this system was obtained very well.