The double-channel digital IR radiometer was developed for eliminating the disadvantages of the IR radiance testing system being used in testing some military infrared products. The double channels simultaneously test the IR radiance and connect the data when the ignition test of an IR radiation product is carried out. Six contrast experiments between the double-channel digital IR radiometer and IR radiance testing system were performed at 25℃ and -15℃. The result indicates that the error of the two systems are all less than 5％, and the difference of the two channels of the double-channel digital IR radiometer is also less than 5％. But 1905A testing system missed out twice and the radiator did not omit anything. The principle, design of key components, calibration and application are discussed in this paper.