There is currently no equipment that can test the spectral response of digital infrared detectors. Therefore, a circuit board device is developed to convert the output of the digital infrared detector into the same output form as the analog detector. The original Fourier spectrometer is used to solve the problem that the digital infrared detector spectrum can not be tested. This method is low in cost, easy to implement, simple in operation, and stable in test performance, and is suitable for various forms of digital detectors. First, the infrared spectrum response test system is introduced, and then the principle analysis of the developed analog-to-digital circuit board is carried out. Finally, this circuit board is implemented in hardware, and the internal test program is written to complete the functional verification. The result shows that the infrared spectrum test system with the newly developed analog-digital circuit board device can test the spectrum of digital area array detectors or linear detectors with different bit width outputs, and the test results are accurate and reliable.