Abstract: Experiments of fractional crystal1ization under high T-P conditions demonstrate that during crystallization of F-bearing alumina-oversaturated granitic magma,an evolutional trend of REE concentrations in fluid phabe coexisting with melt phase is observed： When temperature drops from 750℃ down to solidus(about 570℃)，the REE concentrations gradually decrease. This phenomenon is consistent with the geological fact that REE contents in the upper zones of rare-metal granites are lower than in the deeper zones ．REE mostly tend to disperse in some rockforming minerals(such as biotite)and some ore-forming minerals(such as fluorite and cassiterite)．The rest of REE partition into fluid phase．The evolution characteristics of REE in the F-rich alumina-oversaturated granite system are not favorable for forming hydrothermal deposits of REE.