Abstract: The SEM with EDX plays an important role in study of mineral changes Use of SEM allows direct observation of microforms in mmeral change and characteristics of newly formed minerals.At the same time,it can be used to determine their element composition.The results are of great importance in inter pretation of the conditions and the mechanism for mineral changes.In this paper the application of SEM type KAD-1000B to study of feldspar trans formation is discussed.Under different conditions the feldspar transformed into kaolinite,halloysite,illite,and illite-montmor illonite miner als of transitional type study on mineral changeby SEM is a new way for development of petrology and mineralogy.