The Tiangong-1 hyperspectral imager has a thermal band with wavelength between 8.0 μm and 10.5 μm, it adopts linear array detectors and broom-push method to obtain image. In this paper, results from laboratory radiation calibration are presented. There included image adjust effects, response parameters and linearity of per detector. According to response parameters, effective quantization code and noise code, temperature range of target which can be detected and noise equivalent temperature D-value were obtained. After analyses about propagation of error, the final calibration error was calculated.