Abstract: By means of X-ray diffraction analysis, scanning electron probe microanalysis and optical microscopy, the chemical composition and mineral intercalation and particle size composition of potassium feldspar in Jilin were studied. The results show that main minerals in the ore is potassium feldspar, albite and quartz, and the iron elements are mainly distributed in hematite, limonite and magnetite. Potassium feldspar is present in the form of needle-shaped fine grain and some iron ore is embedded in the microcrystalline base of potassium feldspar and the edge of hole or immersed in gangue mineral, so the ore belongs to a more difficult ore. In the ore that particle size less than 0.0385 mm, the Fe₂O₃ content reaches 2.36%. All that means the sample needs to be desliming, magnetic separation, flotation and pickling in the follow-up treatment to make the product meet the high-end potassium feldspar market requirements.