Abstract: In the field of infrared radiation characteristics measurement, Fourier transform infrared (FTIR) spectroradiometers are commonly used measurement units. The field of view (FOV) directional response function is one of the main sources of uncertainty, which manifests as varying responsivity at different locations when the measurement target deviates from the center of the FOV. Currently, most studies on FOV directional response employ medium-temperature, conventional-sized blackbodies as radiation sources, resulting in limited spatial resolution. In this study, a high-temperature, small-sized blackbody radiation source is used to investigate the FOV uniformity of FTIR spectroradiometers, and the directional response function under a typical FOV of 75 mrad is obtained. The variation of spectral responsivity in the uniform region of the FOV is analyzed, and a correction function for the FOV directional response characteristics is proposed and experimentally verified. The results show that after applying the proposed correction function, the responsivity uniformity in the uniform FOV region increases from 92% to 98%.