FTIR was applied in the analysis of Lapis Micae Aureu samples,and the corresponding spectra were interpreted. The results indicated that the absorption characteristics of spectra of Lapis Micae Aureu samples were similar to those of the layered silicate minerals.The absorption area was divided into four regions：OH stretching vibration absorption at 3 700-3 000 cm-1,H2O bending vibration absorption at 1 620 cm-1,Si—O stretching vibration absorption at 1 000 cm-1 and Si—O bending vibration absorption at 550-400 cm-1.The results showed that,OH vibration absorption intensity was in positive proportion to water content in Lapis Micae Aureu samples and the absorption frequency was related to the type of the interlayer cation.Si—O vibration absorption frequency was affected by Al substituting Si in tetrahedroid,and the absorption frequency reflects the type of cation in octahedron.Thus the infrared spectral characteristics of Lapis Micae Aureu samples could reflect its internal structure,and could be used to evaluate its quality status.