Abstract: In order to obtain experimental evidence demonstrating the relationship between oreforming process and liquid immiscibility in felsic magma,we carried out a series of experiments at high temperature and atmospheric pressure. The experimental results show that the granite-KBF4 -Na2MoO4-WO3 system is ahomogeneous melt at high temperature. With decrease in temperature, however, the melt decomposes into twoimmiscible melts: silicate melt and ore-forming melt. The ore-forming one exists as globules in silicate melt.Mo, Ca, Na, Mg, P, Mn, F, B and OH- are concentrated in these globules. The ore forming melt is characterized with very low SiO2 and Al2O3 concentrations, and very high concentration of MoO3 and CaO; the silicatemelts are significantly enriched in SiO2 and Al2O3. The differences between the two immiscible melts exist notonly in chemical composition, but also in structure. The ore-forming melt structurally consists of [MoO4],[MoOF4], [B(OH)4] and OH;while the silicate melt, [SiO4]. Because of the difference in composition andstructure the two immiscible melts possess different physical properties. Compared to silicate melt, the ore-forming melt has a lower density and viscosity, which permit the globule to behave as bubbles in granite magma,move and concentrate in the upper part of magma chamber. This process is probably responsible for the concentration of ore-forming elements in the upper part of granite they and its immediate aureole.