Abstract: A comprehensive and fundamental research on the mineralogical characters of perlite ore in Xinyang Shangtianti were done for the first time. Optical microscope, X-ray fluorescence spectrometer, X-ray diffractometer, scanning electron microscope, advanced mineral identification and characterization system were used to investigate the mineralogical characters of perlite ore, and the amount of bound water content in perlite ore and its expansion ratio were also tested. Results show that the perlite ore in Shangtianti mostly possess perlitic structure, glassy texture and dense massive structure. The content of amorphous substance is greater than 90%. A small amount of fine particles such as montmorillonite and clinoptilolite were formed at the edge of perlite balls or in the cracks due to devitrification. Besides, trace amount of kaolinite, feldspar, iron ore (limonite), etc. were also detected in perlite ore. For perlite ore, the average amount of TFe is around 0.6%, the bound water is in the range of 4%~6%, and the industrial expansion ratio is greater than 15, and the perlite ore is class I perlite.