Abstract: This paper introduces the research on the monoenergetic X-ray calibration device and detector calibration method carried out by the Monoenergetic X-ray Laboratory of NIM. The energy range of the established monoenergetic X-ray calibration device can cover 5～300 keV, which provides the ground calibration of performance indicators such as energy linearity, detection efficiency, position response, and angular response for space-borne detectors of space science satellites in China. Satellite projects being calibrated include spaceborne detectors for scientific satellites such as SVOM, GECAM, and HXI.