Abstract: Iron is one of the most widely distributed transitional metal elements on the earth, but the research on Fe isotopes lags behind. This article describes the Fe-Isotope testing techniques starting from TIMS to MC-ICP-MS, and its major research progress and status quo. The composition and distribution of Fe elements and Fe isotopes in the nature and their fractionation in both the biological and non-biological processes are also described. Fe isotope geochemistry and their wide application in the fields of paleoceanography, mineral deposits and other branches of earth sciences involve iron sulfides, iron oxides, and iron carbonate minerals -siderite mineralization. The latter is currently considered to be the key to the study of the origin of carbonate dolomite. Through the trace studies of trace amounts of iron and heavy metals in dolomite, we discussed the genetic characteristics and mechanism of the environmental dolomite in the isolated island of the Xisha Islands and its relation to the dolomite problem.