Na-F solutions with different pH were allowed to react under flow conditions with limestone, dolomite and siderite at 300 and 400℃ at 500 bars, in order to understand the geochemical characteristics of the interaction between rock and F-bearing hydrothermal solutions. The mineralogical and chemical composition of these carbonate rocks was studied by chemical analysis, XRD and SEM/EDAX before and after reaction with Na-F solutions. Based on an approximate thermodynamic calculation the formation of alteration phases is discussed. The pH value at room conditions and the contents of K, Na, Ca, Mg, Fe, F, SiO2 and total dissolved CO2 in solution after interaction with carbonate rocks were determined. From solution chemistry data, it is found that the amount of Na and F in the reacted solutions seemed to have roughly similar fluctuations with time, and hence, carbonate might be an effective precipitating agent for Fe in hydrothermal solutions. The present experimental study demonstrates that hydrothermal metasomatism played a very important role in the formation of the Baiyun Ebo iron deposit.