Abstract: A reference material of pure manganese flake for manganese content calibration in X-ray energy/wavelength dispersive spectrometers (EDS/WDS) was developed. The homogeneity and stability of manganese content in the pure manganese flake were examined using electron probe microanalysis (EPMA). The manganese content (mass fraction, %) of the reference material was determined using inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS). The uncertainties of the reference material were evaluated. The results show that the pure manganese flake reference material exhibits good homogeneity and stability in manganese content. The certified value of manganese content in the reference material is 99.48% with an expanded uncertainty of 0.92% (k=2). The developed pure manganese flake reference material for EDS/WDS calibration can meet the calibration requirements of EDS/WDS and provide technical support for manganese element analysis in scientific research and industry in China.