Abstract: Minerals are important composition in coal and coal-ashes. In this study, the coal samples were collected from seam 6 in Huaibei coal field. The minerals and trace elements in the coal and the coal-ash were investigated by INNA, chemical method, X-ray diffraction and scanning electron microscopy. On the basis of the methods, the main species and forming factor of minerals in coal and coal ashes are analyzed. According to the result, the coal ashes are the residues derived from the inorganic and organic matter during coal combustion and the ash is an important and routinely determined characteristics of quality of coal. Coal ashes are mainly consisted of kaolinite, quartz, calcite, pyrite and many trace elements in the studied samples. The concentrations of trace elements and the species of the minerals were changed and the new steady species of minerals were formed during coal combustion.