Abstract: The direct shear experiments of rare earth ore samples before and after leaching are performed to analyze the effect of leaching technology on the physical and mechanical properties of ion-adsorption rare earth ore. The shear strength parameters of rare earth ore are worded out using Coulomb's law. The effect of leaching on the mineral particle size and shear strength of rare earth ore are analyzed through strength experiment results with combinations of sieve analysis test. The experiment results indicate that ion exchanges process in leaching changes the ingredient, granularity and grading of mineral particles. The shear strength and other mechanical properties of rare earth ore mining region change accordingly. The cohesive force decreases by half and the internal friction angle increases by 15 % after leaching. The mineral particle grading deteriorates, but not significantly. This study provides references for the slope stability in rare earth mining and the comprehensive treatment and utilization of tailings after leaching.