The Zhazixi W—Sb deposit, located in the Xuefeng Range, western Hunan, is a typical one of the veinfilled hydrothermal deposits. Scheelite is a widespread mineral in this hydrothermal deposit. In the present contribution, the REE insitu analyses have been performed by laser ablationinductively coupled plasmamass spectrometry (LA-ICP-MS) on scheelite samples collected from the Zhazixi mining district. It is revealed there is obvious REE inhomogeneity among the scheelite samples analyzed in this study. REE concentrations and chondritenormalized patterns can change abruptly among different scheelite grains in the same thin section, even in different part of the same grain. The chondritenormalized REE distribution patterns of scheelite from the Zhazixi deposit can be classified into the MREEenriched type, MREEdepleted type and REEflat type; these three REE patterns can exist independently or coexist in certain scheelite sample. Even in the same scheelite mineral grain in some thin sections, the above three REE patterns can simultaneously appear, probably revealing a complete dynamic evolution process that reflects this scheelite formed as follows: MREE in the early oreforming fluid are incorporated into scheelite, the precipitation of this MREErich scheelite will significantly alter the composition of hydrothermal fluid and produce a MREEdepleted fluid, which results in the subsequent formation of MREEflat and MREEdepleted scheelite. Therefore, LA-ICP-MS method may be a potential tool to identify the dynamic process of oreforming hydrothermal fluids. In addition, cautions have been taken for traditional REE analyses of bulk samples, lest some mistaken information or conclusions should be obtained.