Abstract: Aiming at the problems exist in the permeability of low-grade weathered crust elution-deposited rare earth, sesbania gum, which has an ability of enhancing the permeability, was employed as leach-aid agent to improve the leaching efficiency in this thesis. The effect that the concentration of sesbania gum, the concentration of lixiviant, leaching velocity and liquid -solid ratio have on leaching efficiency were studied through a series of experiments. The experimental result shows that under leaching-aid effect of sesbania gum, the leaching recovery will increases from 87.05 % to 94.17 %, while cutting down 32.56 % of the lixiviant consumption, hence the leaching efficiency of the leaching process is effectively improved.