Abstract: During the process of heap leaching, incrustation is easy to precipitate on the surface of ore, which leads to decrease of the permeability of leaching yard and finally affects the leaching rate.Taking the acid heap leaching technique of a high-slurry high-alkali ore in Yunnan as background, the SEM scanning and X-ray diffraction analysis on the leaching ores of incrustation showed that the  composition of incrustation was mainly CaSO₄, that is because Ca²⁺ was continuously generated, which absorbed the SO₄²⁺ in leaching process.By adding different anti-incrustation agent in experiments, and with the help of scanning electron microscopy, the inhibiting effect of the anti incrustation agent on the incrustation of ores was verified.The mechanism of the anti-incrustation agent was mainly chelate effect and crystal distortion effect.