Weijing pluton is considered the most important uranium source for Nuheting uranium deposit in Erlian Basin. In this paper，the elements action of the pluton under weathering process was analyzed，and the results showed that the CIA values was between 58.67～60.07，reflecting a week weathering
condition under cold，dry climate. In the process of weak weathering，plagioclase weathered firstly，and Ca，Na moved，but potash feldspar was relatively stable，while under the strong weathering，potassium feldspar discomposed obviously. And the decomposition of phosphate minerals release P. The
adsorption of clay minerals leads to the enrichment of Mg and Ca under the condition of strong weathering on the surface. The content of Fe2O3T and FeO decreased significantly，which was more likely to be related to oxidation leaching of magnetite and pyrite. And H，LOI，S and C were significantly reduced
in highly weathered samples，suggesting that the weathering were conducted in dry and oxidized climate conditions. Elements such as Ca，K，Mg，Fe，C and S were firstly migrated，followed by P，Mn and Na，while Ti and Al were stable elements. Iron group elements，such as Cr，Ni，Ti，and REE
trace elements remain stable，Nb，Ta，Zr and Hf，Th，Y high field strength elements and some of the large ion lithophile elements Pb，Rb，Be，Li，were enrichmed to a some extent，while U，V and Sr were significantly emigrated out，and Zr/Hf，Nb/Ta，Th/Sc changed which were constrained mainly
by primary mineral decomposition release and clay mineral adsorption in the process of weathering. The REE patterns of different samples were consistent，but the Y/Ho ratio in weathered sample was significantly higher than that of fresh rocks，which may be mainly related to the abundance of HCO3－ on the
surface. Under the chemical weathering conditions of drought oxidation and enrichment of HCO3－，U is more likely to be leached out，providing an important uranium source for uranium mineralization in Erlian Basin.